Rich Squash Casserole

1 cup grated Gruyere cheese
1 cup ricotta cheese
1/2 cup plain bread crumbs
1 Tbsp. cornstarch
1 1/4 dried basil
1 1/2 dried thyme
3/4 tsp. each salt and black pepper
1 Tbsp. olive oil
8 oz. mushrooms, sliced
1 large onion, chopped
3 large summer squash, sliced 1/4 inch thick
2 large zucchini, sliced 1/4 inch thick

Stir together Gruyere, ricotta, bread crumbs, cornstarch, basil, 3/4 tsp. of the thyme and 1/2 tsp. each of the salt and pepper; set aside.

heat olive oil in a large skillet over medium-high heat. Add mushrooms and onion; sprinkle with remaining 3/4 tsp. thyme and 1/4 tsp. each salt and pepper. Cover; cook 6 minutes, stirring occasionally.

Coast slow cooker with cooking spray. Layer 1/3 of the squash in bottom. Add 1 cup mushroom mixture over squash; sprinkle 2/3 cup ricotta mixture on top. Layer with another 1/3 of squash, the rest of the mushrooms and another 2/3 cup of ricotta mixture. Place remaining squash and ricotta mixture on top.

Cover; cook for 2 hours on high or 4 hours on low. Serve immediately.