This casserole is so yummy and versatile... it started off as tunaless casserole, which was just pasta and veggies but since I discovered Beyond Meat veggie chicken it's evolved into something much more tasty.
cube veggie chicken, or shred it (if you're in the mood for the extra work), and put that in the pot with the veggies and pasta. sit the pot to the side.
in a medium size skillet, heat your 1/4 cup of oil and sautee your diced onion.
once onion is a little soft, sprinkle 1/4 cup of flour into the skillet. work onions around the skillet, making sure they are coated in the flour.
when onions are coated, pour in milk, and stir. make sure the fire is not too high, you don't want to burn the milk. stir a lot. i use a fork and kind of whisk it a bit so it doesn't stick to the bottom of the skillet.
once milk has thickened you can add shredded parmesan and cheddar and stir until it has melted in. add salt and pepper to taste.
your cheese sauce is done! now pour it all over the pasta, veggie, and chick'n and mix it good. once it's mixed, pour it all in your casserole pan and sprinkle with cheese. bake until cheese is melted and a little brown here and there.