Preheat oven to 190°C (Gas mark 5/375°F). Grease and line the base of 3 x 20cm round cake tins.

Place the butter and caster sugar in a large bowl and whisk together until well combined and fluffy.

Add the six eggs, two at a time, whisking after you add each pair. Once the eggs have all been whisked in, add the flour, baking powder, milk and vanilla. Whisk again until fully combined.

Divide the cake mixture into 3 and split between 2 bowls – ⅔ in one and ⅓ in another. Using the gel food colourings, colour the larger portion blue and the smaller portion red. Divide the coloured cake mixture between the prepared tins, 2 blue, one red.

Gently smooth the tops down with a spatula, then bake in the pre-heated oven for around 20 minutes, until the cakes are springy to the touch. Turn the cakes out onto cooling racks and leave to cool before icing.

Whilst the cakes are cooling, prepare the buttercream icing. Whisk the butter until soft and fluffy. Add the icing sugar, a little at a time, whisking as you go until completely combined. Add the vanilla extract and whisk again until combined.

Remove 300g buttercream to fill the cake and a second 300g of buttercream for the crumb coating. Reserve the remaining buttercream for the final coat.

When ready to assemble, secure one of the blue cakes onto a board with a little buttercream. Spread over half of the buttercream you set aside for filling. Add the red cake and repeat the buttercream filling, then top with the final blue cake.

Using a palate knife, spread the buttercream that you set aside for the crumb coating all over the cake. Spinning the cake slowly, use a large cake scraper to even out the top and sides of the cake.

Once the cake is covered in the coating, pop the cake somewhere cool to allow the icing to set a little.

Carefully open one of the packs of HARIBO Starmix by cutting off one of the top corners. Remove the sweets, taking care not to damage the packet as this will be used as part of the cake.

Place the white chocolate in a small microwave safe bowl and gently heat until just melted – stirring as you go. Be careful not to burn it – white chocolate melts quickly!

Coat ⅔rds of a plastic straw with the white chocolate, then stick HARIBO Starmix sweets all over it.

Place the sweet-covered straw on a small plate and pop in the fridge until the chocolate has set.

Spread the remaining buttercream over the cake for the final layer. As before, spin the cake slowly and use a large cake scraper to even out the top and sides.

Push a long bamboo skewer into the top of the cake and then slot the Starmix covered straw over the top of it. The skewer should be pushed well into the cake so that it can securely hold the straw.

Take the HARIBO Starmix packet you prepared earlier, and place it over the top of the straw so that it looks as though the sweets are pouring out of the packet. You can stick the pack to the straw with a little of the melted white chocolate if it doesn’t sit easily in place.

Arrange some of the Starmix sweets in a pile around the base of the straw.

Use the remaining Starmix sweets to create a border around the base of the cake, pressing them gently into the buttercream to hold them in place.