Truffles in small chocolate boxes

Preparation

1. Chop the chocolate in a bowl. Simmer the cream and pour it three times over the chocolate, mixing in the center to obtain a smooth ganache.
2. When the ganache is lukewarm, add the butter in small pieces. Pour into shallow dish, cover and refrigerate for 3 hours.
3. Gently melt the additional 220 g of chocolate. With about 144 g, or 12 g per shell, brush in two regular layers of 1.5 to 2 mm in total twelve silicone imprints 4.5 cm in diameter and 2.5 cm deep; let take 15 minutes between the layers and check that the bottoms and sides are continuous.
4. With about 72 g of the remaining 76 g, form twelve discs of 4.7 cm on baking paper, about 2.5 mm thick. Let shells and discs crystallize for 1 hour in a cool room. If the room is too hot for a firm grip, refrigerate the shells 15 to 20 minutes before unmolding them.
5. Soften the cold ganache for a few minutes at room temperature, without heating it. Gently unmold the shells and then fill them with about 30 to 32 g of ganache each, up to 3 mm under the edge. Roll the surplus into small truffles; the remaining 4 g of shell chocolate can decorate them.
6. Lightly powder the cocoa ganache and place the lids. Refrigerate 30 minutes. Remove a serving disc to reveal the filling; the remaining cocoa is used for additional small truffles and does not need to be fully used.