Heat oil in a 12 inch skillet over medium heat until shimmering. Add the onion, chili powder and 1/2 tsp. salt and cook until onion is softened, about 5 minutes. Stir in the garlic and cook until fragrant, about 30 seconds.

Add the beef and cook, breaking up the meat with a wooden spoon, until almost cooked through but still slightly pink, about 3 minutes. Stir in the tomato puree, ketchup, water, brown sugar and 1/2 tsp. hot sauce. Simmer until the sauce is slightly thicker than the ketchup, about 8-10 minutes.

Season with salt and hot sauce to taste. Spoon mixture over hamburger buns and serve. Good if served with a pickle.