4 pounds yellow squash, sliced (1 pound of squash yields about 2 cups sliced, so you’d need about 8 cups)
4 Tbsp. butter, divided
1 large sweet onion, finely chopped
2 garlic cloves, minced
2 1/2 cups soft breadcrumbs, divided
1 1/2 cups shredded Parmesan cheese, divided
2 cups (8 oz.) shredded Cheddar cheese
1/2 cup chopped fresh chives
1/2 cup minced fresh parsley
1 cup sour cream
1 tsp. salt
1 tsp. pepper
2 large eggs, lightly beaten
1/4 tsp. garlic salt

4 pounds yellow squash, sliced (1 pound of squash yields about 2 cups sliced, so you’d need about 8 cups) 4 Tbsp butter, divided 1 large sweet onion, finely chopped 2 garlic cloves, minced 2 1/2 cups soft breadcrumbs, divided 1 1/2 cups shredded Parmesan cheese, divided 2 cup s (8 oz.) shredded Cheddar cheese 1/2 cup chopped fresh chives 1/2 cup minced fresh parsley 1 cup sour cream 1 tsp salt 1 tsp pepper 2 large eggs, lightly beaten 1/4 tsp garlic salt

In large skillet, cook squash, covered in boiling water, for 8-10 minutes or until tender. Drain well and remove squash from skillet; gently press squash between paper towels to take out remaining moisture and set aside. Then, in same large skillet, melt 2 Tbsp. butter over medium-high heat; add onion and garlic, and saute 5 to 6 minutes or until tender. Remove skillet from heat; stir in squash, 1 cup breadcrumbs, 3/4 cup Parmesan cheese, and the other remaining ingredients, except for the garlic salt. Spoon into a lightly greased 13×9-inch baking dish.

Melt remaining 2 Tbsp. butter and stir with remaining 1 1/2 cups breadcrumbs, 3/4 cup Parmesan cheese, and garlic salt. Sprinkle mixture evenly over the top of the casserole. (If you want, you can also sprinkle another 1/2 cup of Cheddar cheese on the top to make it extra cheesy.) Bake at 350 degrees for 35-40 minutes, or until set. This makes 8-10 servings.