Gather all the ingredients.
Preheat oven to 400 F.
Cut the tops off the bell peppers. The easiest way to do this is to cut around the stem about a half inch from the top of the bell pepper. When you’ve cut the entire way around, gently pull the stem and the top should come off in one piece. Scoop out the seeds and fibers with a spoon.
Place bell peppers cut side up in a baking dish and drizzle ~ 1 tbsp of olive oil. If they are having trouble standing up, just cut a little sliver off the bottom.
Next, slice mushrooms and dice onions.
In a large Teflon frying pan, add 1 tbsp of olive oil on medium-high heat. Without waiting for the oil preheat, add ground beef and break apart with a wooden spoon/spatula. Season with salt and pepper and cook for 3 minutes.
Add diced onions and mushrooms and cook until softened. Approximately 3 minutes.
Add in tomato paste, canned diced tomatoes and stir to combine. Lastly, add Swerve/Monkfruit and continue to sauté until well incorporated and liquid has reduced, approximately 5 minutes.
Remove pan from heat and spoon meat sauce mixture into each bell pepper and top with cheese. Cover bell peppers with foil and bake until desired doneness of the bell peppers, ~25-30 minutes.
Then uncover and bake until cheese is melted and bubbly. Approximately 5 minutes. Enjoy hot!