1. Preheat the oven to 450° F. Rub a baking sheet with oil or butter. 2. In a bowl, mix the ground beef, panko, egg, 1/2 of the chopped onion, garlic powder, chili powder, paprika, cumin, cayenne, and 1 teaspoon salt. Roll the meat into large tablespoon-size balls (will make 15-16 meatballs), placing them on the prepared baking sheet. Arrange the butter around the meatballs. Bake for 15 minutes or until the meatballs are crisp on the outside, but not yet cooked through on the inside.3. While the meatballs are cooking, mix the tomatoes, remaining chopped onions, tomato paste, poblano pepper, black beans, and pickled jalapeños in a bowl—season with salt. 4. Remove the meatballs from the oven, pour over the sauce, and add the cheese. Bake until the cheese is melted, 15 minutes. Serve warm with your favorite chili toppings: cilantro, scallions, avocado, yogurt - and beer bread!