In a small non-stick pan that’s been preheated over medium-high heat, add ground beef, onion powder, garlic powder, crushed fennel seeds, salt and pepper and cook until beef turns nice and golden brown. Transfer the beef to a plate or bowl and add the mushrooms to the hot pan; cook until golden on both sides. Turn off the heat and reserve.
On a well-floured surface (I like to use cornmeal), roll the pizza dough into a thin 10-12 inch disc and lay it on a baking sheet.
Spread tomato sauce evenly on the dough; top with mushrooms and half the bell peppers; add ¾ of the mozzarella cheese, followed by the ground beef, the rest of the bell peppers and sliced olives. Finally, add the rest of the mozzarella cheese.
Bake in the oven for about 10 minutes, until cheese is melted and the crust starts to color on the edge.