Step 1

Heat the oil in a large pot over high heat. When it shimmers, add the onion and pepper, if using, and immediately turn the heat down to low. Season with a pinch of salt and add the chili powder, cumin, and cayenne. Cook, stirring every so often, until the vegetables are softened, 5 to 7 minutes. Add the tomato paste and garlic and cook for another minute.

Step 2

Add ground beef and cook, breaking up the meat with a spoon until no longer pink, 5 to 7 minutes. Stir in the stock and beans, scraping up any browned bits, and bring to a simmer. Reduce heat to gentle simmer, cover, and cook for about 20 minutes.

Step 3

Uncover, add the crushed tomatoes or tomato sauce, and cook, stirring occasionally, until the chili has thickened, about 20 minutes. Taste. If it needs a little bite, add the vinegar. If it needs a little sweetness, add the sugar. If it needs more salt, add a big pinch and cook for 5 minutes more. Taste again, and adjust with more salt, cayenne, vinegar, or sugar. Serve with cheese, cilantro, and scallions on top.