Step 1

To melt chocolate, bring about an inch of water to a simmer in your saucepan. Set the heatproof bowl in the mouth of the pot, making sure the water doesn't touch the bottom of the bowl. Stir chocolate occasionally as it softens. When you have just a few small unmelted chunks, remove bowl from heat (residual heat will melt the rest).

Step 2

To make gold medal, working quickly, dip one biscuit in chocolate to coat, drain off excess; cover both sides with gold shimmer. Repeat with remaining biscuits, melted chocolate, silver shimmer and orange sprinkles to make silver and bronze medals. Stand at room temperature until set. Cut ice-cream wafer in half; spread chocolate over one side of wafer, stand until set. Discard remaining wafer half.

Step 3

Trim cakes; secure two large cakes, long sides together, on cake board with a little frosting. Spread frosting over top and sides of cake.

Step 4

To make the podiums: Cut remaining cake into 6 equal squares; discard one square.

Step 5

Using a little frosting, secure two squares on top of each other to make the gold medal podium. Cut one square in half (so it is half the height); secure to second uncut square to make the silver podium. Leave third square as it is for the bronze podium. Spread frosting all over squares.

Step 6

Using picture as a guide, carefully position podiums on cake. Wrap sour strap round side of cake, cutting to fit; secure with a little frosting, if necessary.

Step 7

Cut the remaining sour strap into 3 pieces to represent ribbons; cut ‘V’ shape in one end of each strap. Position ‘ribbons’ on each podium.

Step 8

Push a skewer into the centre of each podium, making sure to push all the way down to the cake board. Position medals on podiums, leaning up against skewers, trim skewers as necessary, so they are hidden behind the ‘medals’. Use the writing icings to draw Olympic rings on the wafer; position in front of podium.