Heat oven to 180C/gas 160C/gas 4. Grease a 20cm cake tin and line the bottom with a circle of greaseproof paper. If you want to make life easy, simply put all the ingredients (except the cocoa powder) into a food processor and whizz for 1-2 mins until smooth. If you prefer to mix by hand, beat the butter and sugar together, then add the eggs, one at a time, mixing well after each addition. Fold through the flour, milk and vanilla extract until the mixture is smooth.
Divide the mixture between 2 bowls. Stir the cocoa powder into the mixture in one of the bowls. Take 2 spoons and use them to dollop the chocolate and vanilla cake mixes into the tin alternately. When all the mixture has been used up (and if young kids are doing this, you’ll need to ensure the base of the tin is fairly evenly covered), tap the bottom on your work surface to ensure that there aren’t any air bubbles. Take a skewer and swirl it around the mixture in the tin a few times to create a marbled effect.
Bake the cake for 45-55 mins until a skewer inserted into the centre comes out clean. Turn out onto a cooling rack and leave to cool. Will keep for 3 days in an airtight container or freeze for up to 3 months.
Heat oven to 200C/fan 180C/gas 6 and put on a full kettle. Have a large roasting tin ready. Butter 10 squares of foil, each about 15 x 15cm. Butter 10 x 200ml mini pudding tins, dust with flour, then tap out the excess. Cut 10 small circles of baking paper to fit the bottoms and drop one into each tin.
Melt the butter and chocolate together in a pan, heating gently and stirring every so often. Set aside to cool. Meanwhile, put the eggs and sugar into a large bowl and whisk with electric beaters for 10 mins, or until the mix is thick and foamy and holds a trail for a few seconds.
Mix the ground almonds, flour and baking powder together. Splash 1 tbsp amaretto over the biscuits. Fold the cooled chocolate mix into the whisked egg and sugar using a large metal spoon. Follow with the flour mix, then work in the amaretto.
Fill the tins one-third full, then drop in an amaretti biscuit and top up with mix, leaving a 1cm gap between the top of the mix and the edge of the tins. Loosely scrunch a foil square over the top of each tin. Put the tins in the roasting pan and pour hot water around – it should come about halfway up the sides of the puddings. Bake for 30 mins, then insert a skewer into one; a few damp crumbs should stick to the skewer – you don’t want the puds to be totally dry.
Meanwhile, make the fudgy sauce. Melt all of the ingredients together in a heavy-based pan, stirring until the sugar dissolves. Set aside. Keep in the fridge for up to 2 days,then reheat on the hob or in the microwave on High for 1 min. To serve the puddings, turn onto plates and spoon over some of the sauce, allowing it to ooze over the edges. Sprinkle with shards of Salted almond brittle and serve straight away.