Preheat the oven to 350 degrees F

Cut the tops off of the bell peppers. Then remove the seeds and inner ribs. 

Spray a baking dish with cooking spray. 

Place the peppers cut side up in the baking dish. 

Heat the olive in a large skillet over medium heat.

Add in the ground beef and cook for 5 minutes. Use a spatula to break up the meat as it cooks through.

While the beef is cooking break the polenta into small mushy pieces. 

Once the beef starts to brown add in the onion and cook for 4 minutes, stirring often.

Add in the garlic and cook for another minute. 

Add the tomato sauce, Italian seasoning, and polenta to the pan with the beef. Stir to combine. Use the spatula to break up the polenta and combine it with the beef. 

Remove the pan from the heat. 

Stir in ½ cup of cheese to the mixture.

Using a large spoon, evenly stuff the peppers with the beef mixture.

Loosely cover the peppers with aluminum foil and bake for 25 minutes. 

Remove the foil. Sprinkle the remaining cheese over the top of the peppers. 

Return the bell peppers in the oven and cook for another 10 minutes or until the cheese starts to bubble.

Remove from the oven and serve. The peppers will be very hot so watch for steam.