Place a pizza stone or baking sheet in your oven and pre-heat the oven to 450 degrees. On a pizza peel or cutting board, place a piece of parchment sprayed with non-stick cooking oil.
Remove the florets from your head of cauliflower. Place the florets in a food processor or blender and pulse until the cauliflower has the texture of sand. You should have about 2½-3 cups of cauliflower sand.
Transfer the cauliflower sand to a microwave safe bowl and microwave, covered (not with aluminum foil, duh), for 4 minutes.
Let your cauliflower cool completely. (Seriously, it needs to be cool or you will burn the shit out of your hands during the next step. Trust.) When cool, place the cauliflower in a towel and wring it tightly. You want to remove as much moisture from the cauliflower as humanly possible. I recommend doing this in two batches to get your cauliflower really dry.
Place the cauliflower pulp in a mixing bowl and add the cheeses, spices, and the egg. Mix until well combined. Using your hands is your best bet, friends.
Form the dough into a ball and place it on the parchment-lined pizza peel or cutting board. Place a second piece of sprayed parchment on top of the dough ball and roll it out into a circle about 1/6-inch in thickness. Remove the second sheet of parchment and briefly set your pizza aside while you prepare your vegetables.
Place the broccoli, bell peppers and onions on a foil lined baking sheet. Drizzle with 2 tablespoons olive oil and sprinkle with salt.
Carefully transfer your dough to the hot pizza stone/baking sheet. Place your vegetables in the oven along with your dough. Bake for 8-10 minutes until the dough is golden brown. Carefully remove it from the oven along with your vegetables.
While your dough is baking, quickly sauté the mushrooms in 1 teaspoon olive oil for 3-4 minutes until tender. Briefly set aside.
Spread the sauce over the pizza dough and sprinkle with an even layer of mozzarella. Top with the roasted vegetables, sautéed mushrooms and crumbled goat cheese.
Return the pizza to the oven for another 5-7 minutes until the cheese is melted and bubbling slightly.
Let your pizza cool for 2-3 minutes before slicing to make sure that the crust stays intact. Get weird with your guilt-free pizza. Vegetables are so hot right now.