1: Roll out 200 g brioche dough into a flat round cake 8 inches (20 cm) diameter. Lay the cake on a baking sheet, then glaze the top. Leave in a warm place to rise for one hour.
2: Roll 100 g marzipan (almond paste) into a long " sausage about half an inch (1 cm) thick.
3: Cut the marzipan into half-inch (1 cm) chunks. Cut the prunes into quarters.
4: Preheat the oven to 360°F (180°C). Push the marzipan pieces into the top of the well-risen cake.
5: Stick a piece of prune on top of each piece of marzipan.
6: Glaze the top of the cake again, then sprinkle with caster sugar.
If you would like a stronger Armagnac flavour, add 2 tablespoonsful at the end of mixing the brioche dough. You can make this recipe using an enriched bread dough (pain brioché), rather than a classic brioche dough, but the cake will be plainer.