Step 1

Preheat the oven to 350 degrees. Grease a 9-inch square casserole dish.

Step 2

Melt the butter in a medium skillet over medium heat. Cook the squash and onions until the onions are translucent, about 10 minutes. Remove the skillet from the heat.

Step 3

In a large bow, whisk the egg with the sour cream, salt and pepper. Fold in the squash and cheddar cheese until well combined.

Step 4

Spread the mixture evenly in the prepared baking dish. Bake for 25 minutes, or until browned and bubbly around the edges.

Step 5

Mix together the pork rinds and parmesan cheese. Sprinkle the topping evenly over the casserole and bake for 5 more minutes, or until the topping is lightly browned.

Step 6

Leftovers can be stored in an airtight container in the refrigerator for up to 2 days.