Coffin cake

Preheat the oven to 170ºC, gas mark 3. Grease and line a 900g loaf tin with baking parchment. In a large mixing bowl, use a balloon whisk to mix the sugar and oil until combined. Whisk in the eggs, vanilla, almond extract, milk and lemon juice until smooth.

Sift the flour and baking powder into a separate bowl, then mix in the ground almonds with a pinch of salt. Tip the dry ingredients into the wet ingredients and whisk until smooth and combined. Pour into the lined tin and bake for about 1 hour or until risen and a skewer inserted into the centre comes out clean. Leave in the tin until cool to the touch, then turn the cake out onto a wire rack to cool completely.

While the cake is baking, make the ganache. Gently bring the double cream almost to the boil in a saucepan. Remove from the heat and add the dark chocolate along with a pinch of salt. Swirl the pan so the cream covers the chocolate, leave to stand for 2 minutes, then mix to a smooth ganache. Transfer to a bowl and cover to cool completely (about 3 hours at room temperature or 1½-2 hours in the fridge). Once set, whisk the ganache in a stand mixer or using an electric hand mixer until paler in colour and holding peaks when the whisk is removed.

To construct the coffin cake, use a serrated knife to level the top of the loaf, then cut into the shape of a coffin by slicing off 2 small triangles from the top ⅓ of the loaf and 2 larger triangles from the bottom ⅓. Slice the coffin in ½ horizontally to make 2 sponges. Use the ganache to coat the sides of both sponges and the top of 1. Put in the fridge to chill and set for 30 minutes.

Meanwhile, make the cream filling: put the mascarpone in a bowl and use a balloon whisk to whisk until velvety. Mix in the cream, vanilla and green food colouring until smooth – it will be quite a stiff mixture as it needs to hold the weight of the top sponge.

Once the ganache has set, spread most of the green cream over the sponge without the ganache topping. Drizzle over a few spoonfuls of jam, carefully dripping some down the sides, then sandwich with the other sponge, ganache-side up. Dollop the remaining green cream over the top of the cake and embed the googly eyes (if using) into the blobs. Drizzle over more jam.

Put the marshmallows in a heatproof bowl and microwave for 20-30 seconds until melted. (Alternatively, set the bowl over a saucepan of gently simmering water, stirring occasionally, until melted.) Leave for 30 seconds, or until cool enough to handle, then use lightly oiled fingers to spread the marshmallow into a web across the top of the cake (this bit is very messy and is easiest to achieve if the melted marshmallows are still warm). Serve in slices.