Squash Casserole

This is one of your dad's top 10 favorite recipes.  He loves it.  I love it.  We all love it.  It's particularly good in summer when squash is fresh, local, and plentiful.

Ingredients:
6 large summer squash (8-9 small squash)
1 large Vidalia onion sliced and then slices cut in half
2 tablespoons olive oil
1/2 cup sour cream
1 cup shredded cheddar cheese
1/2 grated Parmesan cheese
1 and 1/2 sleeves whole wheat Ritz crackers

Preparation:
In a large sauce pan, add oil and heat to high.
Add onion and squash to oil, seasoning with salt and pepper, and saute until softened.
Line a strainer with a clean dish towel and pour squash/onion mix in.
Wrap up the mixture and squeeze out as much of the excess liquid as possible.
Add to a bowl and mix in shredded cheddar, Parmesan cheese, and sour cream.
Spray a 9x13 baking dish with Pam and add mixture, smoothing out.
Use your hands to crush Ritz crackers over the top of casserole until covered.
Bake at 350 for 30 minutes.
If you like things cheesy, pull it out and add more shredded cheddar cheese over the casserole and bake another 5-10 minutes.