Chop your vegetables: Dice the onion and mince the garlic., Brown the meat: In a skillet over medium-high heat, brown the beef until it develops a brown crust. Drain excess fat., Combine the ingredients: In the slow cooker, add the browned beef, diced onion, minced garlic, kidney beans, black beans, diced tomatoes, tomato paste, and beef broth. Sprinkle the chili powder, cumin, smoked paprika, and season with salt and pepper to taste. Stir to mix everything nicely., Set your slow cooker: Cover and cook on low for 6-8 hours or on high for 3-4 hours., Final touches: About 30 minutes before serving, taste your chili and adjust the seasoning. If you want to thicken the chili, remove the lid for the last 30-60 minutes of cooking., Garnishing: Once your chili is ready, ladle it into bowls and top with your desired garnishes.