Add 2 pounds ground beef, 2 teaspoons kosher salt, and 1/2 teaspoon black pepper. Cook, breaking up the meat with a wooden spoon, until browned and cooked through, 6 to 8 minutes. Add 2 tablespoons chili powder, 1 tablespoon ground cumin, 1 tablespoon unsweetened cocoa powder, 2 teaspoons dried oregano, 1 teaspoon paprika, and 1/4 teaspoon cayenne pepper if using. Stir to coat the meat and cook for 1 minute more.