"Beef, chili beans, and a special surprise ingredient give this chili a savory flavor unrivaled by other chilis. Serve topped with diced raw onion, sour cream, and shredded Cheddar cheese for a mouth-watering delight! Believe it or not, the secret is the ketchup (NOT catsup) that adds just the right flavor to the sauce; use more or less as desired. Use sauteed fresh mushrooms for a special treat! Seasonings may be added to taste. If you want it really hot, use hot chili beans and add more chili powder and cayenne pepper or include hot peppers!"
Heat a large skillet over medium-high heat. Cook and stir beef, about half the sweet onion, and garlic powder in the hot skillet until completely browned, 5 to 7 minutes.
Mix tomato chunks, chili beans, tomato sauce, kidney beans, ketchup, and tomato paste in a large pot; bring to a boil and reduce heat to low. Stir the ground beef mixture and mushrooms into the tomato mixture; season with chili powder, sugar, salt, and black pepper. Cook chili at a simmer, stirring occasionally, until the flavors blend, about 45 minutes. Top individual servings with diced sweet onion to serve.