Combine the yeast, sugar, and warm water; mix well and allow to rest for several minutes until bubbles begin to form. This is called “proofing.” Mix the melted butter and the salt. In a large bowl combine the flour, eggs, and the butter and yeast mixtures. Beat by hand until smooth. Place in a buttered bowl, cover with plastic wrap, and set in a warm, draft-free place to rise until light and doubled in bulk, about 1 to 1½ hours. Punch the dough down and refrigerate it for at least one hour.

Generously coat one dozen small brioche molds with butter. Roll the chilled dough to a thickness of ½ inch on a floured work surface and with a 3-inch round cutter cut out circles. Place a chunk of chocolate in the center of each circle and roll the dough up, around, and completely covering the chocolate. Place the dough in the prepared mold. Repeat the procedure for each circle of dough. If you want to be authentic, make little balls from the remaining dough and push them on top of the dough in the molds, to make top knots. Depending on the size of your molds and how large you make the brioche you may make as few as 10 or as many as 15. Place the molds on a heavy-duty baking sheet. Make sure they have a few inches between them. Let the dough rise, uncovered, in a warm, draft-free place until the brioche are double in volume.

When ready to bake, preheat the oven to 400 degrees with the rack in the center position. Gently paint each one with an egg wash made by mixing the egg yolk and the light cream. Take care not to get any wash down inside the pan—this will prevent the brioche from rising when baking in the oven. Sprinkle the tops with the baker’s sugar. Bake for 15–20 minutes, or until the tops are golden brown. To make sure they are fully cooked, remove one brioche from the mold and tap the bottom—there should be a hollow sound. If the bottom is still soft, you can remove all the brioches from their molds and continue baking them an extra 5 minutes. These are best served right from the oven with raspberry jam, but they can easily be refreshed (even after freezing) by being warmed in a 350 degree oven for 10 minutes.