Chop the onion.

Brown the ground beef and chopped onion in a large pot or skillet over high heat.

Reduce the heat to medium.

In a separate bowl, mix the cornstarch, oregano, and garlic powder into the pizza sauce.

Add the pizza sauce mixture to the meat mixture.

Stir well to combine.

Cook until the sauce thickens and bubbles.

Add the Cheddar cheese and Mozzarella cheese by thirds, mixing well after each addition until melted and smooth.

Cut French or sourdough bread into bite-sized chunks.

Serve the fondue hot with the bread cubes for dipping.