Preheat your oven to 375°F (190°C). Slice the tops off each bell pepper and carefully scoop out the seeds and membranes, creating a hollow cavity to fill.
Using a small paring knife, carve faces into each pepper to resemble mini Jack-o'-Lanterns, making eyes, a nose, and a jagged mouth for a festive look.
Place the carved peppers on a baking sheet and drizzle them lightly with olive oil, then season with salt and pepper inside and out.
Fill each hollowed pepper with the cooked rice or quinoa, then top with a portion of the cooked ground meat or beans and shredded cheese, pressing gently to pack the filling inside.
Arrange the filled peppers on the baking sheet and bake in the oven for about 25-30 minutes, until the peppers are tender and slightly blistered, and the cheese is melted and bubbly.
Remove from the oven and let cool slightly. Serve these pumpkin-like mini Jack-o'-Lanterns warm, enjoying the visual fun and savory aroma.