Dice the onion into 1/2-inch pieces, chop the celery and green bell pepper, and set aside in separate bowls. In a small bowl, combine the chili powder, ground cumin, cayenne pepper, dried oregano, ground black pepper, garlic powder, and sugar—this spice blend will be your flavor foundation and will distribute evenly when mixed with the beef. I prefer freshly ground chili powder when I can find it because it has a much brighter, more complex flavor than pre-ground.

Heat a large skillet over medium-high heat and add the ground beef, breaking it into small pieces as it cooks. Once the beef is no longer pink and has started to brown (about 5-7 minutes), sprinkle the spice blend from Step 1 over the meat and stir well to coat evenly. This technique blooms the spices in the rendered fat, deepening their flavors significantly before they go into the slow cooker. Cook for another 1-2 minutes until fragrant, then carefully pour off any excess fat, leaving just a light coating in the pan—using 93/7 lean beef means there won't be much fat to drain.

Transfer the browned, seasoned beef from Step 2 to your slow cooker, scraping any browned bits from the pan. Add the diced onion, celery, and green bell pepper from Step 1, then pour in the tomato puree and tomato juice. Add the drained and rinsed pinto beans and red kidney beans (rinsing removes excess sodium and starch for a cleaner flavor). Stir in the kosher salt and mix everything thoroughly to combine. I like to stir the chili well at this point to ensure all the flavors are distributed evenly throughout.

Cover the slow cooker and set it to low. Cook for 4 hours, which allows the vegetables to soften completely, the beans to absorb all the flavors, and the spices to meld into a cohesive, rich sauce. Resist the urge to lift the lid during cooking, as this releases heat and extends the cooking time. At the 2-hour mark, you can quickly stir if desired to check doneness and ensure even cooking, but keep this brief.

Once the chili has cooked for 4 hours, it's ready to serve. The beef should be tender, the vegetables soft, and the sauce rich and flavorful. Ladle into bowls and serve warm. This chili actually tastes even better the next day as the flavors continue to develop, so consider making it ahead if you have time.