1 small head Earthbound Farm Organic Cauliflower (about 1 pound, separated into 1-inch florets, about 5 cups)
2 tablespoons truffle oil or olive oil
  Sea salt and freshly ground black pepper
  Flaky Multigrain Pie Crust dough for a single-crust pie (wrapped in parchment and refrigerated, or use your favorite recipe, refrigerated and ready to roll out)
  unbleached all-purpose flour (for rolling the dough)
1 tablespoon Dijon mustard
2 tablespoons olive oil
1 large Earthbound Farm Organic Yellow Onion (cut in half through the stem end, then cut crosswise into 1/8-inch-thick slices, about 3-1/2 cups)
2 large eggs
1 cup mascarpone cheese
1/2 cup heavy (whipping) cream
1/4 teaspoon Freshly ground white pepper
  pinch freshly grated nutmeg
1 cup shredded Gruyère cheese (3-1/2 ounces)
2/3 cup freshly grated Parmesan cheese (about 1-1/2 ounces)