Heat 1 tablespoon olive oil in a large skillet over medium heat
Add the chopped onion, chopped summer squash and chopped carrot to the skillet and cook until the onion is soft and translucent.
Add the minced garlic clove and cook for 1 minute
Add the ground beef and cook until you can't see any more pink
Add the chopped whole tomatoes, the tomato sauce, green onions, brown sugar, chili powder, mustard powder, Worcestershire sauce, salt, and pepper. Turn the heat down to medium-low and let it simmer for about 15 minutes (you might need to turn the heat all the way down to low)
Spoon the beef and veggie mixture onto some store-bought hamburger buns.