Weigh out the dried fruit, peel and the ground almonds into a large mixing bowl.
Add the lemon zest and juice and pour over the rum. Mix well and cover with cling film and leave overnight.
Preheat the oven to 170C/150C Fan/Gas 3.
Line a 30cm square tin on the inside with two layers of greaseproof/baking paper.
Line the outside with a double thick strip of newspaper.
Weigh the flour and mixed spice into a bowl and set aside.
Weigh the butter and sugar into a large mixing bowl and beat together well until light and fluffy. (I use a Kenwood mixer for this)
Slowly add the beaten eggs to the butter and sugar, incorporating well and only adding small amounts at one time. If the mixture curdles add some of the flour.
Once the eggs have been mixed in add the flour and spice and mix again until smooth and glossy.
Stir the dried fruit well, redistributing the rum and any liquid at the bottom of the bowl and now add the butter and flour batter to the soaked fruit.
Using a large metal spoon, fold together until all the fruit is evenly distributed.
Spoon the mixture into the prepared tin and press down well, smoothing the top with the back of the spoon or a spatula.
Bake in the centre of the preheated oven for 30 mins then turn the oven down to 155C/ 140C Fan/Gas 2.
Cook for a further 4 hours, checking the cake regularly towards the end of the cooking time to make sure that it is not burning and not cooking quicker than expected.
When the cake is cooked it should be evenly risen and will have begun to shrink away from the sides of the tin. When gently pressed it should spring back.
Remove from the oven. Leaving in the tin until completely cold.
Turn the cake out leaving the greaseproof paper on it and wrap in foil to store.