Cook the ground beef until done and drain the grease. While the ground beef is cooking, steam the cauliflower rice in the microwave. VERY IMPORTANT: After the cauliflower has cooked, you must press out as much liquid as possible. Place the cooked cauliflower rice in a mesh strainer, then place several paper towels on top of the cauliflower and use your fist to press very firmly on the cauliflower rice. Repeat this process, switching out the wet paper towels with dry paper towels until there is no more liquid draining/dripping out of the strainer.
Combine the ground beef and cauliflower rice. Add the tomato sauce (use the tomato sauce with basil, garlic, and oregano for added flavor but check carb content), sour cream, and seasonings. Mix well. Check the flavor and add additional seasonings if desired.
Wash and dry bell peppers. Cut the tops off the bell peppers and remove the seeds and white membrane.
Fill the peppers with the ground beef mixture and place in a baking dish or muffin pan. SEE RECIPE NOTES BELOW FOR SOFTER BELL PEPPERS.
Bake, uncovered, at 350 for 20-25 minutes. For softer bell peppers, cover with foil before baking (see note below). Remove from oven, and top with cheese. Return to the oven for another 5-10 minutes to melt the cheese. Use the broiler to brown the cheese to your liking.