Preheat the oven to 180C Fan (200C, 350F, Gas Mark 4) and cover a baking sheet with baking parchment.
Combine the eggs with the sugar in the bowl of a food mixer and mix on medium for around 10 minutes.
Add the mixed spice to the frothy egg and sugar mix and fold in with a spatula or spoon.
Roughly chop the whole almonds and add them to the batter along with the marzipan, mixed peel, cranberries and lemon zest. Mix them in gently.
Add the sifted flour and fold this into the mixture. The mix will be very thick, you’ll struggle to stir it. If it’s really tough, you can add a tablespoon or two of milk and mix it in well.
Spoon the batter into a disposable piping bag, without a nozzle and cut an opening of about 5cm.
Pipe two rows 25cm long by 5cm wide on the prepared baking tray. Alternatively you can divide the dough in two and pat the dough to form two sausages on the baking tray.
Sprinkle the loaves with the sliced almonds and bake for around 30 minutes or until a cocktail stick comes out clean. The cake may still be a bit soft, but this is OK, because you’re going to cook the cake again.
Immediately transfer the loaves to a cutting board and slice them with a long straight knife (don’t use a bread knife, this will make them crumble) on the diagonal, about 1cm thick.
Place the slices cut side down on the same baking sheet and bake for a further 7-10 minutes until crisp, but still pale.
Let cool on the baking tray, before storing in an airtight container. They should keep their crunch for at least a week.