Preheat your oven to 350°F (175°C).

In a large skillet, melt 3 tablespoons of butter over medium heat.

Add in the sliced squash and diced onion, and sauté until they are soft and lightly golden, about 10–12 minutes. Let them cool slightly.

In a large mixing bowl, combine the sour cream, cream of chicken soup, beaten eggs, shredded cheddar cheese, garlic powder, paprika, salt, and black pepper.

Stir in the sautéed squash and onion mixture until everything is well blended.

Spoon the mixture into a greased 9x13-inch baking dish.

In a small bowl, mix the crushed Ritz crackers with melted butter, then sprinkle this over the top of the casserole.

Bake in the preheated oven for 30–35 minutes, or until the casserole is golden brown and bubbly.

Allow it to sit for about 5 minutes before serving.