Heat oven to 400°F. Spray 12x8-inch (2-quart) ceramic or glass baking dish with cooking spray.
Cook and drain spaghetti as directed on package, using minimum cook time.
Meanwhile, in 8-inch skillet, heat oil and melt butter over medium heat. Add mushrooms and garlic; season with salt and pepper. Cook 4 minutes, stirring occasionally. Set aside.
In large bowl, mix eggs and cheese. Season with salt and pepper. Add mushrooms and spaghetti; toss to coat. Pour spaghetti mixture into casserole. Sprinkle bread crumbs over top.
Bake 20 to 25 minutes or until top is golden brown.