Preheat the oven to 350 degrees.
Mix the flour, baking powder, almonds and cocoa in the SliceSy® with the bamix®. Add the powder sugar, salt, butter and eggs in a bowl and mix them into the dough, using the bamix® whisk.
Using a small ice cream scoop, place small balls of dough about 3-4cm in diameter, onto the wax paper on a baking tray about 2in apart. Bake in the preheated oven for 8–10 minutes. Let sit on the baking tray for 3-5 minutes, then move to a cooling rack for 10-15 minutes to completely cool.
For the custard, mix 4 tbsp. of milk with the cornstarch, using the bamix® whisk, and stir until smooth. Place the rest of the milk, sugar and vanilla extract in a pot and bring it to the boil. Take the pot from the stove and stir in the cornstarch slurry. Place the pot back on the stove and let simmer for 3 minutes while constantly stirring the custard until creamy. Fill into an icing bag, pipe onto the cooled cookies and dust with powder sugar.
