Thong cake (Flip-flop cake)

Blue and Yellow Thong cake

This lovely cake can be baked for many different special occasions. I even made one for a Christening!!


900g Pale blue sugar paste, coloured with Wilton Royal blue and Americolor Royal Purple (for cake, straps, plaque and flower centres)

200g Dark blue sugar paste, coloured with Wilton Royal blue and Americolor Royal Purple (for flowers)

300g yellow sugar paste (for top layer)

1 hollow plastic dowel

pale blue Royal icing for piping

clear A4 sheet of plastic acetate

Make the Dark Chocolate Mud Cake

Use an 8″ square pan but fill it with more batter than usual following the quantities below
500g unsalted butter
400g dark chocolate
10g (2 tablespoon) instant coffee
2-2/3 cups warm water
380g (2 cup) caster sugar
520g (3 cups) self raising flour
60g (1/2 cup) cocoa
4 eggs
2 teaspoon vanilla
1. Grease and line base and sides of cake pan with one thickness of baking paper, bringing paper 5cm above side of pan.
2. Combine chopped butter, chopped chocolate, coffee, and water in a saucepan.
Stir over low heat until chocolate is melted. Cool 15 minutes. Transfer mixture to bowl of mixer.
3. Add caster sugar to mixture and beat well until dissolved. Add sifted flour and cocoa, lightly beaten eggs and vanilla.
4. Pour mixture into prepared pan.
5. Bake at 150C for 1 hour 45 mins. Test with skewer. Cool cake in pan.

Make the Dark Chocolate Ganache

1.2 kg (2lb 10oz) dark chocolate, finely chopped

500ml (17.5 fl oz) pure cream

Method: Heat the cream until it just starts to bubble, pour over chocolate (which you have blitzed in the food processor to coffee granules size) and let it sit for about a minute to melt. Use a hand whisk to blend it all together then set aside to cool.
Your ganache at this point will be thin. You will have to let it set overnight until it thickens to a slightly thicker peanut butter consistency. Since I don’t have the patience to wait, I just let it cool to room temperature and then pop it in the fridge (don’t cover because you might get condensation). It would  usually set in the fridge in about an hour or two. If it sets too hard, just microwave it in 10 second intervals (keep mixing it whenever you take it out).

Making the templates

Draw around a thong and enlarge the line drawing in a photocopier to around 14.5 inches long (my AUS size 10 thong needed to be enlarged by 140%). You may have to enlarge in two steps if your copier is only A4 size. If your copier does not enlarge images, you will have to draw an enlargement by hand.

This is a right hand thong so make sure you don’t accidentally flip your templates and end up with left hand pieces that won’t fit your cake!!!

Copy this shape twice onto thick card. One will be covered in foil to make the set up board and the other will eventually be covered in cling film to make a top board to help with ganaching the sides of your cake.

Your paper template will later be reduced by 1/4″ all round and used to cut out the thong shape from the cake slab.

Making the templates
Making the templates
Make the cake board (rectangular) and the set up board (thong shape)
As it is next to impossible to purchase rectangular cake boards exactly to the size you need, it is best to make your own from 6 or 9 mm MDF covered in foil. Below is a picture of my efforts in making a rectangular board and a thong set up board at the same time. I use PVA glue spread by my fingers to do the job and it works well. Please note that I used the rectangular board with the yellow / orange thong cake at the very bottom of this blog. N.B. (another method I use is to cut the thong set up board out of a large square of gold or silver set up board. This way you won’t need to cover the board.)Glue on the metallic foil
Glue on the metallic foil
Glue and overlap the edges neatly
Glue and overlap the edges neatly
Ready for action
Ready for action

Slice the cake into 3 layers

Place your 8″ square cake on a turntable and cut the dome from the top (if necessary) of the cake to get a levelled surface. Place one hand on top of the cake. Hold a long serrated knife in the other hand, making sure to keep the knife level, then slice the cake twice horizontally to make three even layers. Spread each layer with syrup (whisk 100g of apricot jam with 100ml boiling water until smooth) as this will reduce the amount of crumbs when ganaching, help the ganache to stick to the cake and keep your cake moist. Then cut one layer in half to 8 x 4 in.
Cutting the cake into 3 layers
Cutting the cake into 3 layers
Brushing each layer with apricot syrup
Brushing each layer with apricot syrup

Make and fill a rectangle

Take one of the half layers and sandwich it on to the end of one normal layer with ganache. Put the other normal and half layer on top and sandwich with ganache. You should now have an 8″ x 12″ rectangular cake.

Assembling the layers
Assembling the layers

Build up the cake

Take your initial paper thong template and make it slightly smaller by cutting off 1/4″ – 1/8″ all round (this space will be filled with ganache later on). Place the template on top of your cake (the template will be too long for the cake but don’t worry) and using a sharp knife held at right angles, cut around it. Build up the shape of the thong with the cut offs using ganache as glue. Using some ganache to stick the shaped cake on the set up board. Brush the sides with the syrup.

Reducing the size of the 'cutting template' to leave room for the ganache

Reducing the size of the ‘cutting template’ to leave room for the ganache
Placing the template on the cake
Placing the template on the cake

Apply ganache to the sides and top

Quickly cover the sides and top of the cake with a thin crumb coat of ganache. This will seal the cake and make it easy to add the next layer of ganache and achieve a perfect smooth finnish. Place the cake in the fridge till the outside is nice and firm to the touch.
Before applying the second layer of ganache, cover the remaining thong shaped piece of card with cling film and place on top of cake. Using the top and bottom card shapes as a guide add the ganache and smooth it off with a straight edge such as a ruler or set square. Pop the cake back in the fridge to firm up then remove the card and cling film and smooth some extra ganache over the top of the cake to fill any gaps.
Using a top board and set square to smooth the sides
Ready for the sugar paste
Ready for the sugar paste

Cover with sugar-paste

Knead 900g of pale blue sugar-paste to a pliable dough and roll to 1/8″ thick. Brush the top and sides of the cake with a little water as this will help the sugar-paste to glide onto the cake and also help it stick. Smooth the top of the cake first with a smoother. Next smooth the sides by gently pulling the sugar-paste away from the side before smoothing down with your hands and then the smoother. Roughly cut away the overhanging sugar-paste with scissors, knife or a pizza cutter. Carefully trim the sugar-paste around the base with a small knife. Now stick your cake to the display board with some syrup, Royal icing or edible glue.

Using the cake smoother
Using the cake smoother

Apply the top layer

Roll out yellow sugar-paste to about 1/8 in thick. Place the thong template on top and cut around it with a small knife or pizza cutter. Brush the top of the cake with syrup. Gently lift the sugar-paste and place it on top of the cake. Manipulate the sugar-paste till you get a good fit. Use a smoother to smooth it off and help stretch it if needed.

Using the template
Using the template
Using the pizza cutter
Using the pizza cutter
Applying the top layer
Applying the top layer

Prepare the toe area

Insert the hollow plastic dowel into the correct spot in the toe area using the template as a guide. Leave 4 cm (1 1/2″) of the dowel above the cake. Clip off any excess with scissors. Roll out some yellow sugar paste to 1/8″ thick. cut out a strip 5 x 2 cm (2 x 3/4″ ). Wrap the strip around the skewer and secure with a dab of water or edible glue. Because my dowel was made from yellow plastic and it matched the colour of the thong, I didn’t bother covering it in sugar paste. Fill the hollow dowel with yellow sugar paste as best you can and insert a cocktail stick as in the image below. The cocktail stick will help to anchor the straps and central flower. Mark the position of the straps (towards the back of the thong) with a sharp knife using the template as a guide. Cut out two acetate strips 2.5 cm wide and longer than needed (cut off any excess later). Join the strips at right angles and secure with sticky tape. Make a small hole in the centre with a pin and slip over the end of the cocktail stick. Cut the end off the cocktail stick now but leave a little bit sticking up to help secure the flowers. Decide how long your acetate straps need to be and cut off any extra at an angle while leaving enough to be inserted into the cake as an anchor.

Cut out two pale blue sugar paste straps to fit and attach with edible glue.

To make edible glue

Add 2 tablespoons of warm water to a quarter teaspoon of Tylose Powder and allow the Tylose powder to melt. Don’t worry if at this stage the glue appears not to be blending. Put a lid on the container and leave it in the refrigerator overnight and in the morning you will have a perfectly clear and ready to use glue.
The glue should be a dripping consistency. If it is too thick, just add a little more water and stir with a toothpick .
The edible glue should be stored in the refrigerator when not in use.
To apply the glue, use a good quality paintbrush and brush on to the area where you are going to be working. Leave until it begins to dry a little so that the area is just tacky to touch.

The acetate straps

The acetate straps
Adding the sugar paste straps
Adding the sugar paste straps

Make the flower decorations

Roll out the dark blue and the remaining pale blue sugar paste to 3 mm (1/8″) thick. Using a small flower cutter, cut out up to 30 flowers and a similar number of flower centres in the pale blue. You will also need one large dark blue flower and a circular pale blue plaque to write your birthday message on. You can stick the flowers onto the thong in a random pattern but I have measured mine so that they are spaced 6.5 cm apart.

I used a piping bag with a size 00 nozzle. The RI was make up of 10g of real egg white, 70g sifted icing sugar, 3 drops acetic acid and water added a few drops at a time. Mix all ingredients together with a hand held electric mixer and a few drops of water. Add edible colouring and a few more drops of water until your RI (Royal Icing) reaches the required consistancy: it should take 7 seconds for stirred RI to flatten out. If your RI is too stiff add some more water and test again. If it is too soft,add more sifted icing sugar and test again.

Cutting out the flowers
Cutting out the flowers

Blue and Yellow Thong cake

Blue and yellow thong cake

Blue thong_080313_7874 1mb
Thong cake

Black and White Thong Cake

Another variation to match the party invitations.
Another variation to match the party invitations.
Stripe Thong Cake with Matching cupcakes and surf board toppers
Stripe Thong Cake with matching cupcakes and surf board toppers

4 thoughts on “Thong cake (Flip-flop cake)

  1. I blog quite often and I seriously thank you for your content.
    This great article has truly peaked my interest.
    I’m going to book mark your site and keep checking for new details about once a week. I subscribed to your Feed too.

    1. Thanks Denny, I love my website and blog and I can spend hours trying to make it look better and read better.I only manage to post a new tutorial about once a month but I get such a thrill when I see it in print. I love creating images of my cakes with unusual backgrounds and I spend hours on photoshop. There really is little time left for baking, LOL!

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