Grease a baking tin, line with baking paper and grease again. Preheat the oven to 180˚C (350˚F).
Cream the butter with the sugar. Add the eggs one at a time. Sift in the flour and mix again. Add the salt, baking powder, vanilla and almond flavoring. When everything is mixed well, pour the batter into the pan and bake in the oven for about 50 minutes.
The cake is done when a skewer comes out clean.
Filling
Toast the cashews in the oven until light brown. Grind the nuts as finely as possible. In a saucepan, add the margarine, condensed milk, water and cashews. Stir well with a wooden spoon until the mixture thickens slightly. Remove from heat, add vanilla and stir well.
When the cake is baked and cooled, cut it in three. Drizzle the bottom layer with the liqueur of your choice and top with a layer of cashew filling. Place the other slice of cake on top and repeat the process.
Once the cake is filled, spread the cashew nut paste all over the outside of the cake. Do not allow the cashew filling to cool as it will set and you will have to reheat it.