Digestives: Add the flour, baking powder and salt to a food processor. Pulse until combined. Add the cold butter and pulse until it is evenly combined.
Add enough milk and pulse until it the dough just starts to pull together.
Place onto a well-floured surface and knead until you have a smooth dough.
Roll the dough until it is about 1/8” thick and then cut out circles with a cookie cutter that are about 2 1/2” in diameter.
Poke holes around the outside of the biscuit to create a nice pattern, place onto a baking sheet and bake at 175C/350F for 15-20m or until golden around the edge.
Custard Creams: Put the butter, sugar, eggs, custard powder and vanilla into a food processor and blend until creamy. Add the flour and pulse until the mixture clumps together. Remove from the food processor and shape into a flat rectangle. Wrap in cling film and chill in the fridge for 30m.
Once chilled, pinch off small pieces of dough and roll them out on a lightly floured surface. Cut into rectangles biscuit shapes using a crinkled rectangle cookie cutter or a pastry wheel. Repeat with the remaining dough.
Place onto a baking sheet and bake for 8-10m and 180C or until golden at the edge.
To make the filling, beat the ingredients together until they are light and fluffy. Pipe the filling onto one side of the biscuit and sandwich the second biscuit on top.
Chocolate Bourbons: Beat the butter and sugars together until light and fluffy. Add the golden syrup and vanilla, and beat again.
Sift in the remaining dry ingredients and stir together with a spoon until your dough clumps together. Gently shape into a rectangle and chill in the fridge for 30m.
Once chilled, pinch off small pieces of dough and roll them on a lightly floured surface. Use a pastry wheel to cut long rectangular biscuits and poke small holes around the edge using the end of a toothpick. Repeat with the remaining dough.
Chill for a further 30m then bake for 10-12m at 130C.
To make the filling, melt the chocolate and set aside to cool for at least 10-15m.
Beat the butter and sugar together until light and fluffy, then slowly pour in the melted chocolate.
Pipe onto the base of a cooled biscuit and sandwich a