Classic Beef Chili

Heat oil in a large Dutch oven over medium heat. Add onion and garlic; cook, stirring often, until starting to soften, 3 to 5 minutes. Add beef and cook, breaking it up with a wooden spoon, until no longer pink, about 5 minutes. Stir in chili powder, cumin, coriander, salt and cayenne; cook, stirring, until fragrant, about 1 minute. Stir in water and sweet potato. Bring to a simmer and cook, stirring occasionally and adjusting the heat as necessary to maintain a simmer, until the sweet potato is softened and beginning to break down, 6 to 8 minutes. Add beans, crushed tomatoes and diced tomatoes; return to a simmer and cook, stirring occasionally and adjusting the heat as necessary to maintain a gentle simmer, until the sweet potato starts to melt into the chili, 15 to 20 minutes. Serve topped with cheese and scallions.