Preheat your oven to 350°F. While it heats, prepare the bell peppers by carefully cutting them in half lengthwise and removing all seeds and white membranes inside. Rinse them briefly and pat dry with paper towels. Arrange the pepper halves cut-side up in a baking dish (9x13 inch or similar size), creating a snug fit so they hold their shape during baking.

In a large mixing bowl, combine the ground beef, bread crumbs, tomato sauce, minced onion, salt, jalapenos, garlic, and smoked paprika. Mix everything together gently but thoroughly with your hands or a wooden spoon until the ingredients are evenly distributed. I find that using my hands gives me better control and ensures the seasonings are evenly mixed throughout the meat without overworking it, which keeps the texture tender.

Divide the filling mixture from Step 2 evenly among the pepper halves, pressing it gently into each one to pack it firmly but not so hard that it compacts. The filling should mound slightly above the pepper rim. Pour 1/4 cup water around the base of the peppers (not directly on top of the filling), which will steam the peppers and keep them tender as they cook.

Cover the baking dish tightly with foil or a lid and place it in the preheated 350°F oven. Bake for 45 minutes. The cover traps steam, which gently cooks the peppers while keeping them from drying out and allows the filling to cook through completely. I like to check at the 35-minute mark to make sure the water hasn't evaporated completely—if it has, add a splash more to prevent sticking.

After 45 minutes, carefully remove the foil or lid (watch out for the hot steam). Bake uncovered for an additional 15 minutes at 350°F. This step allows the top of the filling to brown slightly and develop a bit of color and texture, while the peppers finish softening and any remaining liquid reduces. The peppers should be fork-tender and the filling should be heated through.

Remove the baking dish from the oven and let it rest for 5 minutes before serving. This brief resting period allows the peppers to firm up slightly, making them easier to handle and eat. Serve the peppers warm directly from the baking dish, or transfer them to individual plates.