In a large bowl, beat egg whites until stiff. In another bowl, beat butter with sugar until fluffy, then beat in egg yolks.
Melt chocolate with a little water in a saucepan over low heat, then add the butter mixture. Stir in almonds and flour. Mix to incorporate, then fold in the egg whites.
Preheat oven to 200 C / Gas 6. Transfer mixture into a baking tray lined with baking parchment. Smooth over. Bake for about 10 minutes on the bottom shelf. It should be moist on the inside, but dry on the outside.
Leave to cool slightly and cut into small squares. Stick two squares together with jam and dip into the melted chocolate. Allow to set.