Mashed Potato, Spinach, And Squash Casserole

About 2 hours before serving: In 5 quart saucepan over high heat, add water to cover and cook potatoes 30 minutes or until tender.

Drain. Cool potatoes slightly. Peel potatoes.

In large bowl with mixer at low speed, beat potatoes, sour cream, milk, 2 tablespoons butter, 1/2 teaspoon salt and 1/8 teaspoon pepper until smooth and fluffy. Set aside.

Preheat oven to 350 degrees F.

In small bowl, mix well thawed frozen squash with 1 tablespoon butter and 1/8 teaspoon salt; set aside.

In second small bowl, beat egg slightly, add thawed frozen spinach, grated onion, 1 tablespoon butter and 1/8 teaspoon salt. Mix well and set aside.

In 2 quart deep glass casserole or glass souffle dish, evenly spread one third of mashed potatoes, then a layer of squash mixture, then another third of mashed potatoes, then spinach mixture and top with remaining potatoes.

Bake casserole 40 minutes or until heated through.

Remove from oven, sprinkle cheddar cheese over top of potatoes and let stand a few minutes until cheese melts.