Step 1

Preheat oven to 375F/190C. Spray a 9" x 13" casserole dish or large baking sheet with non-stick spray or olive oil

Step 2

Heat olive oil in a large non-stick frying pan over medium-high heat and squeeze sausage out of the casings and add to the pan, breaking apart with your fingers as you add it. Cook until sausage is nicely browned, breaking apart with a turner or potato masher (affiliate link) as it cooks.

Step 3

While the sausage cooks, cut 12 pepperoni slices in halves and the rest into fourths. Grate cheese if needed, or measure out desired amount of pre-grated cheese. Cut peppers in half and remove the seeds and cut out the stem end.

Step 4

When sausage is nicely browned, push it to the side and add the onions and garlic. Turn heat to medium and cook onions and garlic 2-3 minutes.

Step 5

Add the sauce and the dried oregano, turn heat to low, and simmer until the sauce is reduced and thickened. (You should be able to see the bottom of the pan if you pull your turner across it.)

Step 6

Turn off heat, let the mixture cool for a few minutes, then add the chopped pepperoni and 2 cups grated Mozzarella, stirring gently so it's well-mixed with the sausage mixture.

Step 7

Fill each pepper with the pizza-stuffing mixture, packing it in so all the stuffing is used. (It's easiest to hold the pepper in your hand over the pan while you fill and then add it to the baking dish.)

Step 8

Bake peppers 20 minutes. Then remove from the oven and add a generous pinch of grated cheese and four pepperoni halves to the top of each pepper. Put back in the oven and bake 25 minutes more, or until the cheese is nicely browned, peppers are cooked, and the stuffing mixture is bubbling hot. Serve hot