Preheat oven to 425F
In a large bowl, combine crust mix with warm water and garlic powder until well blended. Knead dough into a smooth ball, about 2-3 minutes. Cover and let rest for at least 15 minutes.
Spread garlic and olive oil in a 9-inch round cast iron skillet. Sprinkle with salt and parmesan.
Roll dough into a 13-inch circle, carefully transfer the dough onto the skillet, tucking along the bottom edge and pressing up the side evenly.
Spread 1 pizza sauce pouch onto the bottom of the dough and layer with 1 cup cheese, 1/2 cup pepperoni, 1/2 each of the sautéed mushrooms, green pepper, onion, and black olives.
Drizzle the second pouch of pizza sauce on top; layer with remaining cheese, pepperoni, sautéed mushrooms, green pepper, onion, and black olives.
Bake for 25 minutes or until the crust is golden brown. Cut pizza into 8 wedges and serve.