Dough

Filling

1. Preparing the Filling: Sauté the onions in extra-virgin olive oil until translucent, about 5 minutes. Add the garlic and cook for 1 minute. Add the mushrooms and cook until they soften, about 5 minutes. Add the roasted red pepper and cook for 2 or 3 minutes. Turn off the heat and season to taste with salt, pepper, and fresh herbs. Cool the mixture (it can be made a day or 2 ahead of time).
2. Preparing the Brioche Base: Roll the 10.6-ounce piece of brioche dough on a lightly floured surface so that it is round and no more than ¼ inch thick. Use a 9-inch spring form pan without the bottom or an entremet mold, or a cake pan with a round of buttered parchment paper in the bottom to ensure easy release of the tart. Butter the side walls of the pan. Drape the dough over the pan, allowing as much dough as possible to fall into the pan, but leaving a rim of dough about 2 inches wide overhanging the top. Refrigerate the pan for at least 10 minutes to relax the dough. Remove from refrigeration and draw the overhanging dough into the pan as you press your fingers into the side walls of the pan. Don’t trim the excess dough yet.
3. Making the Crown: Take the 1-pound, 1-ounce piece of brioche dough and divide it into 40 small pieces, each weighing .4 ounces (10 to 12 g). Solicit help if you can, as this can take a lot of time. Round each piece into a tight ball.
4. Filling and Finishing the Tart: Spread the ricotta cheese over the base. Spread the cooled vegetable filling (or filling of your choice) over the ricotta, and sprinkle Parmesan cheese over the vegetables if desired. Top the filling with the little brioche balls, leaving a little space between each so they have room to expand during proofing and baking (you may have a few balls left over—this is better than crowding the balls). Trim the excess dough that still overhangs the walls. Proof for about 40 minutes at 80°F. Egg wash the balls and bake for about 35 to 40 minutes at 380°F. Lower the temperature by 10°F or 20°F if the dough is coloring too quickly. A full bake is important to ensure the bottom of the tart is cooked through. Cool for 30 minutes before carefully removing the pan.