Using the same pan, add the yellow squash rounds. Saute for 10 minutes, or until softened. Then season with salt and red pepper flakes. Mix both the onion mixture and squash in a large baking dish until well combined.
Place the whipped cottage cheese in a bowl and mix together with an egg, ¼ cup parmesan, fresh parsley, and dried basil.
Fold the cottage cheese mixture and half of the breadcrumbs with the squash in the baking dish. Top with shredded cheese, remaining breadcrumbs, and parmesan. Randomly add small chunks of butter throughout.
Bake in a 350F oven for 25 minutes, or until the casserole is set and the top is golden. Serve immediately with fresh parsley for garnish.
Recipe by Slice of Jess at https://sliceofjess.com/lightened-up-yellow-squash-casserole/