For Brioche: Sprinkle yeast over milk in large mixing bowl; let stand 5 minutes. Combine flour, sugar and salt, beat in alternately with eggs and blend until dough is very smooth and elastic. (For best results, use standard mixer with a paddle attachment, mixing for approximately 10-15 minutes total.) Beat in butter, a tablespoon at a time, until well incorporated (dough will be very soft and sticky); continue to mix for 3 minutes more. Remove dough from bowl and shape into a ball. Transfer to a large buttered bowl, cover with plastic wrap and let rise in a warm place until doubled in size, approximately 2 hours. Punch down, reshape into a ball, cover and refrigerate overnight.
After refrigeration, preheat oven to 375°F Turn dough out onto lightly floured board; quickly form into loaf shape. Place dough in buttered 8x4-inch loaf pan; let stand at room temperature 20 to 30 minutes, or until dough just begins to soften (dough will rise slightly).
Transfer dough to oven, lower the temperature to 350°F and bake until golden brown and loaf sounds hollow when tapped, about 50 minutes. Let cool for several minutes, unmold while still warm and transfer to a wire rack to cool to room temperature.
For Brioche French Toast:
Mix egg, milk, vanilla and cinnamon in a bowl with a fork. Melt the margarine in a pan large enough for all 4 slices of toast/brioche. Dip each slice of brioche/toast into the egg mixture. Fry in the pan until golden and crunchy.
For Foie Gras with Wild Mushroom Mixture:
For the fricassee: Melt the butter in a medium saucepan over moderate heat. Add the shallot and sauté until the shallots are softened. Add the mushrooms and continue to sauté until the mushrooms are tender and start to caramelize, about 12-15 minutes. Add the port wine and reduce until the wine is almost evaporated. Add the stock and fresh thyme and simmer until reduced to a sauce consistency, approximately 10 minutes. Season to taste with salt and freshly ground pepper. Keep warm.
For the Asparagus-Mushroom mix:
Melt the butter in a small saucepan. Add the wild mushroom and sauté until lightly caramelized, about 8 minutes. Add the Asparagus and sauté, about 5 minutes. Add the vinegar, cook 1 minute and then add the red wine and simmer until the mixture has a jam-like, syrupy consistency, about 7-10 minutes. Cool to room temperature.
Heat a medium sauté pan over medium heat. Season the foie gras medallions with salt and pepper. Place the medallions in the pan and cook, turning once, until golden brown on both sides, approximately 2 minutes on each side (keeping rare). Take care not to burn the medallions and lower the heat if they brown too fast. Remove the medallions and pour out all but 1 tablespoon of the fat. Add the cooked mushroom fricassee and heat through.
Place slice of brioche in the middle of a warmed plate.
Add a nice spoon of mushroom fricassee in the middle of the brioche and spread.
Lightly coat the mache with the truffle oil and place on top of the fricassee.
Place a small scoop of the Asparagus-Mushroom mix on top of the fricassee.
Then put the sautéed foie gras on top of everything.
Sprinkle with a little high-quality sea salt and shave a little truffle (if available) over the mache.