Preheat oven to 150°C / 130°C fan / Gas 2. Double-line a deep 20cm round tin.
Divide marzipan into thirds. Roll one third into a 20cm circle for the middle layer. Roll another third into a 20cm circle for the top. Roll remaining third into 11 equal balls.
Beat butter and muscovado sugar for 4–5 minutes until pale and fluffy.
Add eggs one at a time, beating well. Add flour if mixture curdles.
Sift in flour, baking powder, and spices. Fold gently.
Add dried fruit, cherries, mixed peel, zests, and brandy. Fold until evenly distributed.
Spoon half the batter into the tin. Place marzipan circle on top. Add remaining batter and level.
Bake for 2–2½ hours until skewer comes out clean. Cool completely in tin.
Brush top with apricot jam. Place marzipan circle on top and crimp edges. Arrange 11 balls around the edge.
Brush marzipan and balls with beaten egg. Toast under a hot grill or with a blowtorch until lightly golden.