Preheat oven to 160°C / 140°C fan / Gas 3. Grease and double-line a deep 20cm round cake tin.
Beat butter and muscovado sugar together for 4–5 minutes until pale and fluffy.
Add eggs one at a time, beating well after each. Add a spoonful of flour if the mixture starts to curdle.
Sift in flour, baking powder, mixed spice, and cinnamon. Fold gently. Add milk and fold again.
Add mixed dried fruit, glacé cherries, lemon zest, and orange zest. Fold until evenly distributed.
Spoon into prepared tin and level the top. Scatter flaked almonds and demerara sugar over the surface.
Bake for 1 hour 15 minutes to 1 hour 30 minutes until a skewer comes out clean. Cover top with parchment if it browns too quickly.
Cool in tin for 20 minutes, then turn out onto a wire rack to cool completely.