1toast the almonds lightly: preheat the oven to 180°C. Place almonds on an oven tray; bake for about 5-6 minutes or until browned. Cool.
Place the chocolate and a knob of butter in a double boiler or in a heatproof bowl set over a saucepan of simmering water. Stir until melted then remove from heat.
2Add the egg yolks, sugar and vanilla seeds to the bowl and beat together for five full minutes until light and fluffy. Add half teaspoon of baking ammonia dissolved in 20 milliliter of very strong espresso coffee. Gradually add melted chocolate, two tablespoons of Rhum and continue beating–Finally add flour and almonds and stir with a spoon until well combined (do not overmix). You’ll obtain a rather compact, sticky dough. Cover and refrigerate for 30 minutes.
3Put the dough on a floured surface (the dough will be a little sticky) and form the dough into a long roll with the width of three fingers and the height of one.
Place the rolls on the sheet that you’ve previously covered with baking parchment and make sure they’re a bit distant from each other since the dough is going to rise quite a lot. Press the rolls gently with your hands to flatten them a bit.–Bake for 20-25 minutes (180°C). Remove from the oven and set aside to cool.
4When the biscuit has cooled, cut the roll diagonally at about one finger width intervals. Place each biscuit disc onto a baking tray and return to the oven (160°C) for a further 10 minutes, or until crisp and cooked through.