Place the Instant Pot on the Sauté function. Add the olive oil and garlic.

Cook until the garlic becomes fragrant.

Add the cream of mushroom soup and green beans to the pot. Add salt and pepper to taste. *I didn't add any water or broth to the Instant Pot for the green beans. The soup was enough for me. If you wish you can add a cup of water or broth and drain it before baking.*

Close the pot and seal. Cook in Manual High-Pressure Cooking for 15 minutes.

When the Instant Pot indicates it has finished, quick release the steam. Turn the Instant Pot to the sauté function.

Combine the flour and water in a small bowl to create a slurry. Add the slurry to the pot.

Add half of the shredded cheese and stir.

Cook for a couple of minutes until the cheese has melted.

Place the mozzarella cubes throughout the casserole. Top with the remaining shredded cheese, panko breadcrumbs, and fried onions. Serve.