Gratin: Sweet Potato & Butternut Gratin
Ingredients
- 1 med-large (1 lb.) baking potato
- 1 lg. (8 oz.) sweet potato
- 1 sm. butternut squash (long thin neck)
- 2 Tbls. butter
- 1 oz. pancetta (Italian bacon), chopped
- 1/4 c. chopped shallots
- 2 garlic cloves, minced
- 1/4 c. unbleached all-purpose white flour
- 1 t. chopped fresh thyme (1/4 t. dried)
- 1/2 t. salt
- 1/2 t. pepper
- 2 c. milk
- 3/4 c. Parmigiano-Reggiano cheese, grated
- 1 Tbls. unbleached all-purpose white flour
- 1/3 c. shredded Gruyere cheese
Instructions
Preheat oven to 375 degrees. 350 degrees if using a glass dish.
Peel and cut potatoes and squash into 1/8-inch thick slices. Keep each variety separate.
Heat a large pot of water to boiling. Add baking potato slices and cook for 4 minutes or until almost tender; remove with a slotted spoon and place in a large bowl. Do not drain water.
Add the sweet potato slices to the boiling water and cook for 4 minutes; remove with a slotted spoon and place in the large bowl.
Add the squash slices to the boiling water and cook for 4 minutes; remove with a slotted spoon and place in the large bowl. Set aside while making the sauce.
Melt butter in a medium saucepan over med-high heat. Add pancetta; cook 1 minute. Add shallots and garlic; cook 2 minutes, stirring constantly.
Lightly spoon 1/4 c. flour into the pan, stirring constantly with a whisk; cook 1 minute. Stir in thyme, salt and pepper.
Gradually add milk, stirring constantly with a whisk; cook over medium heat until slightly thick (about 3 minutes), stirring constantly.
Remove from heat for about 5 minutes. Using a whisk, stir in Parmigiano-Reggiano and stir until cheese melts.
Sprinkle vegetables evenly with 1 Tbls. of flour.
Arrange potatoes and squash in alternating layers in a broiler-safe 11 x 7-inch baking dish coated with non-stick cooking spray. Spoon sauce over potato mixture. Top with Gruyere cheese.
Bake for 40 minutes. If top isn’t crusty and golden brown, broil 3 minutes. Let stand 10 minutes before serving.