Sweet Potato and Butternut Gratin

Ingredients

• 1 pound baking potatoes peeled cut into 1/8-inch-thick slices
• 0.5 teaspoon pepper black freshly ground
• 2 tablespoons butter 
• 8 ounces butternut squash peeled cut into 1/8-inch-thick slices
• 5 tablespoons flour all-purpose divided
• 1 teaspoon thyme sprigs fresh chopped
• 2  garlic clove minced
• 0.1 teaspoon ground pepper red
• 1.5 ounces gruyere cheese shredded
• 2 cups milk 2% reduced-fat
• 1 ounce pancetta chopped
• 3 ounces parmesan fresh grated
• 0.5 teaspoon salt 
• 0.3 cup shallots chopped
• 8 ounces sweet potatoes and into peeled cut into 1/8-inch-thick slices

Equipment

• frying pan
• sauce pan
• oven
• knife
• whisk
• baking pan
• broiler
• measuring cup
• slotted spoon

Directions

1. Preheat oven to 37
2. Melt butter in a small saucepan over medium-high heat.
3. Add pancetta; cook 1 minute.
4. Add shallots and garlic; cook 2 minutes, stirring constantly. Weigh or lightly spoon 1 ounces (about 1/4 cup) flour into a dry measuring cup; level with a knife.
5. Add to pan; cook 2 minutes, stirring constantly with a whisk. Stir in thyme. Gradually add milk, stirring constantly with a whisk; cook over medium heat until slightly thick (about 3 minutes), stirring constantly. Stir in Parmigiano-Reggiano; cook 3 minutes or until cheese melts. Stir in salt and peppers.
6. Remove from heat.
7. Cook baking potato in boiling water 4 minutes or until almost tender; remove with a slotted spoon. Cook sweet potato in boiling water 4 minutes or until almost tender; remove with a slotted spoon. Cook butternut squash in boiling water 4 minutes or until almost tender; drain.
8. Sprinkle vegetables evenly with remaining 1 tablespoon flour. Arrange potatoes and squash in alternating layers in a broiler-safe 11 x 7-inch baking dish coated with cooking spray; spoon sauce over potato mixture. Top with Gruyre.
9. Bake at 375 for 40 minutes.
10. Preheat broiler. Broil 3 minutes or until golden.
11. Let stand 10 minutes.