1 pound extra-lean ground beef
½ cup frozen, diced onions (see note)
2 garlic cloves, minced
1 teaspoon kosher salt
⅛ teaspoon black pepper
1 6-ounce can tomato paste with Italian herbs
2 tablespoons packed brown sugar
2 tablespoons yellow mustard
1 tablespoon hot sauce, such as Frank’s Red Hot
½ cup frozen, diced green peppers (see note)
2-3 tablespoons water (see note)
Whole wheat buns