Preheat oven to 375 °F. Cut the tops off the bell peppers and remove seeds and membranes.
Carve faces into the peppers using a small paring knife — triangle eyes, jagged smiles, whatever your Halloween heart desires.
Cook the filling: Heat olive oil in a skillet, sauté onion and garlic until fragrant. Add ground beef, cook until browned.
Stir in cauliflower rice, tomato sauce, paprika, chili powder, cumin, salt, and pepper. Cook for 3–4 minutes.
Mix in half of the cheese and stir until melted through.
Stuff the peppers: Fill each “pumpkin” with the hot mixture, top with the remaining cheese, and replace the tops like little lids.
Place peppers upright in a baking dish. Add a splash of water to the bottom to keep them moist.
Bake for 25–30 minutes, until the peppers are tender and the tops lightly browned.
Let cool a few minutes before serving — they’ll look like glowing pumpkins fresh from the oven!