Prepare the dark truffle

It must be made the day before.

1. Put the whipping cream in a saucepan over the heat.
2. When the cream comes to a boil, remove it from the heat and add both chocolate couvertures.
3. Keep stirring until all the chocolate is well incorporated and there are no lumps left.
4. Transfer the mixture to a glass bowl and cover it with cling film touching the chocolate.
5. When it is cold, put it in the refrigerator until the following day.
6. The next day, temper the chocolate before using it.
7. Transfer the truffle to a saucepan that can go directly over the heat and work it with your hand, kneading it until it can be stirred with whisks.
8. Keep the saucepan over the heat for only 10 seconds, remove it from the heat to work the chocolate, and put it back over the heat for another 10 seconds; repeat this process until it has a texture similar to Nocilla.

Prepare the sponge cake sheet

Note: have the tray ready and the oven hot before starting, because this is a mixture without chemical leavening and, once whipped, it should not wait long before being placed in the mould and baked.

1. Place the rack on the second guide from the bottom.
2. Preheat the oven to 240 ºC.
3. Use a flat tray with 1 cm low sides and grease it with melted butter so that the paper adheres well to the base.
4. Line the base of the tray with baking paper extending about 10 cm beyond one of the long sides; the paper must not cover the sides, only the bottom.
5. Press the paper against the base of the tray.
6. Brush the baking paper with melted butter.
7. Sift the flour or flour mix.
8. Start whipping the egg whites to stiff peaks with half of the sugar.
9. Halfway through whipping, gradually add the sugar, without stopping whipping, and then the honey, until you obtain a firm mixture that forms the typical peak.
10. In another bowl, whisk the yolks with the other half of the sugar until they double in volume.
11. Transfer 1/4 of the egg whites to the bowl of yolks and stir gently with a spatula.
12. Add the sifted flours in two batches, while continuing to stir gently with a spatula.
13. Fold in the remaining 3/4 of the egg whites, stirring gently but without wasting time.
14. Spread the mixture over the tray and distribute it evenly.
15. Smooth it with the help of a long palette knife or a spatula.
16. Bake at 240 ºC for about 6 minutes, with the oven door slightly open; place a wooden spoon in it so that it does not close completely.
17. Check the baking by opening the oven and carefully touching the sheet with your hand; if it sticks, it is not cooked enough yet.
18. Do not brown it too much, because it must remain a slightly moist sheet that can be rolled without breaking.

Temper the filling chocolate and prepare the bulgars

1. Temper the filling chocolate following the same procedure of stirring and briefly heating it over the heat, without burning it.
2. Cut the sponge cake sheet into three approximately equal parts, parallel to the short side.
3. Spread a layer of truffle over one of the pieces.
4. Roll the sheet onto itself, from one long side to the other, applying a little pressure.
5. Once the three sheets are filled and rolled, put them in the refrigerator for 30 minutes so that they firm up a little.
6. Meanwhile, prepare the chocolate coating bath by melting the chocolate with the butter in a bain-marie.
7. Use a somewhat wide and not very deep container so that you can coat the bulgars and remove them easily.
8. Keep stirring so that the chocolate does not burn.
9. Allow the coating to cool to 32 ºC.
10. Prepare the oven rack with aluminium foil underneath.
11. Remove the rolled sheets from the refrigerator and cut them into individual portions, without making them too large; clean the knife after each cut.
12. Coat the bulgars in the couverture chocolate, dropping them into the bath and removing them with two forks.
13. Leave them to drain on the rack until the couverture chocolate hardens.
14. If you wish, sprinkle small chocolate granules over them.
15. Return them to the refrigerator for a while, without removing them from the rack, so that the chocolate finishes setting.