If necessary cut buns (not all the way through) and reheat chili. Grill the hot dogs until lightly charred: about 10 minutes.
Cover large baking sheet with parchment paper for easy cleanup. Arrange hot dog buns on baking sheet cut side up. Using the broiler brown the buns rotating the baking sheet several times.
Preheat oven to 375 degrees. Spread half of each cheese evenly over the inside of the buns. Add the grilled hot dogs and any condiments. Top with 1/3 cup chili and the remaining cheese.
Bake in preheated oven for 15-20 minutes or until the cheese is melted and everything is heated through.
Top with onions and any other desired toppings. Serve promptly.
