Step 1: Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add ground beef and cook, breaking it apart with a spoon, until browned. Drain any excess fat.
Step 2: Add the diced onion and green bell pepper to the skillet. Sauté for 5-7 minutes, or until softened. Stir in the minced garlic and cook for another minute until fragrant.
Step 3: Pour in the tomato sauce, ketchup, brown sugar, yellow mustard, apple cider vinegar, chili powder, and smoked paprika. Stir well to combine all ingredients.
Step 4: Bring the mixture to a simmer, then reduce heat to low, cover, and let it cook for 10-15 minutes, stirring occasionally. This allows the flavors to meld and the sauce to thicken.
Step 5: Taste and adjust seasoning with salt and pepper as needed. If you prefer a thicker sauce, remove the lid and continue to simmer for a few more minutes.
Step 6: While the sloppy joe mixture simmers, toast your hamburger buns. You can do this in a toaster, under the broiler, or in a dry pan until lightly golden.
Step 7: Spoon a generous amount of the warm sloppy joe mixture onto the bottom half of each toasted bun. Top with the other bun half and serve immediately with your favorite sides.