Cook squash and potatoes in boiling water until tender, about 15 minutes.
Drain squash and potatoes; return to pot. Add milk, salt, black pepper, nutmeg and red pepper. Mash with potato masher until fluffy. Set aside to cool slightly.
Preheat oven to 375 degrees F.
Sauté onion in oil in large skillet until softened, for about 5 minutes. Add garlic; sauté 1 minute. Remove to a plate.
Crumble beef into skillet; cook until browned, about 3 minutes. Stir in basil, oregano, cumin, salt, thyme, pepper, reserved onion mixture and flour. Add tomatoes and green beans. Bring to boiling. Lower heat; cover and cook 10 minutes. Spoon into 13 x 9 x 2-inch glass baking dish.
Beat egg into squash mixture. Spread over filling, making decorative swirls. Sprinkle with paprika.
Bake in 375 degree F oven 40 minutes or until bubbly and top is golden brown. Transfer baking dish to wire rack to cool for 20 minutes before serving. Makes 8 servings.