DS came home 2 weeks before half term with a volcano project. In a flash of inspiration I thought this might be the perfect opportunity to 'kill 2 birds with one stone'. So, here is our erupting volcano cake.
For the cake we used Nigella's Buttermilk Birthday Cake recipe - we made up 1.5 times the amount. We baked the cakes in a standard springform tin and one half of a giant silicone cupcake mould that I had lingering at the back of the cupboard.
Once baked we cut out the centre of the smaller cake so that we could fit a small pot into it (for the bicarb/lemon juice eruption) and then sandwiched together with the chocolate sauce - (DS1 won't touch a cake with butter icing so it is out in our house).
I had used some red food colouring to dye some of the white buttons red for the lava spill. DS2 decided that this volcano would be snow capped and so he and his younger brother set about decorating the cake mountain. The green jelly was spooned in clumps around the bottom of the cake in place of vegetation!
When we were ready to erupt we first stuck 2 cake sparklers inside and lit them. Then, we placed the small pot inside the top of the cake with a teaspoon of bicarb in it and poured the lemon juice/food colouring mix in for the lava flow. Finally an ash cloud of icing sugar descended.
I have included the link to our video - complete with DH's crazy, slightly out of time soundtrack - to show the eruption.
DS2's verdict - "it actually tastes really nice too". Having completed this I breathed a sigh of relief that one more homework project had been completed only to hear "Oh, but I want to make a model of a volcano as well." Hooray for enthusiastic children!
Cake Ingredients:
250g plain flour (I replace 50g of flour with cocoa powder for a chocolate version)
1/2 tsp baking powder
1/4 tsp bicarbonate of soda
200ml buttermilk (or 75g yogurt mixed with 125ml semi-skinned milk)
1 tsp vanilla extract
125g softened butter, plus extra for greasing
200g caster sugar
3 large free-range eggs
Decoration (apart from the buttons):
Lime Jelly
200g Dark/Milk Chocolate + 75g Butter melted together
Icing Sugar
Eruption:
Mini cake sparklers
Lemon Juice (1 lemon was enough) mixed with Red food colouring.
Method (I follow this in a very haphazard way):
Preheat the oven to 180C/350F/gas 4. Butter cake tin/moulds.
Sift the flour, baking powder, bicarbonate together. Mix the buttermilk (or yogurt mixture) and vanilla extract.
Cream the butter and sugar together. Beat in the eggs one at a time, adding a little of the flour with the last one.
Gradually add the rest of the flour with the buttermilk, one after the other, until thoroughly mixed.
Pour into the tin and bake for about 30 minutes or until well risen and pale golden brown. Loosen the sides of the cake with a round-bladed knife and turn out onto a wire rack to cool.