Stuffed Peppers with Frozen Cauliflower Rice

Slice off pepper tops and set aside. Place peppers on a microwave-safe plate. Microwave peppers on high until partially cooked, about 3 minutes.

Meanwhile, remove and discard stems from tops. Dice remaining flesh; set 1/2 diced top flesh aside and reserve remaining 1/2 for another use.

Place frozen riced cauliflower in a microwave-safe bowl. Microwave on high for 4 minutes, stirring halfway.

Heat olive oil in a large nonstick skillet over medium-high heat until hot, about 1 minute. Add beef, carrots, celery, mushrooms, onion, and reserved diced peppers; cook until onion begins to turn translucent and beef is nearly cooked, about 5 minutes. Stir in Italian seasoning, red pepper flakes, oregano, salt, and black pepper; cook 1 minute. Add cauliflower and garlic; cook and stir until beef is browned and crumbly, breaking up any chunks with a spoon, 2 to 3 minutes.

Preheat the oven to 350 degrees F (175 degrees C).

Stir diced tomatoes, tomato paste, and basil into beef mixture; cook until nearly all liquid evaporated, about 5 minutes.

Off heat, cool beef mixture slightly, about 5 minutes, then divide and stuff into peppers. Stand peppers upright in a baking dish.

Bake in the preheated oven until peppers are tender and filling is hot, about 30 minutes.