1. Melt 1/2 cup butter in large skillet over medium high heat. Add vegetables, cook uncovered for 20 min or so, stirring often. Add salt and pepper. Spoon squash mixture into a 9x13 baking dish- set aside.
2. Preheat oven to 350°F. In a med. saucepan, melt remaining 2 Tbsp. butter over low heat. Stir in crushed crackers and cheese. Sprinkle over casserole.