Fall Harvest Gratin
An easy and delicious autumn dish from Laura Pensiero of Rhinebeck’s Gigi Trattoria
This gratin pairs nicely with a tossed salad or served with simply roasted chicken, beef, or pork. The New York State Cheddar béchamel can be added to many fall gratins, but the sharp cheddar and cayenne-induced kick marries best with tart apples.
Makes 8-10 servings
For the NYS Cheddar Béchamel:
• ¼ cup butter (½ stick)
• ¼ cup flour
• 1 qt milk
• ¼ tsp cayenne pepper
• 2 cups grated sharp NYS cheddar
• 1 Tbsp salt
• pinch nutmeg
For the Gratin:
• 2 Tbsp butter
• 2 medium onions (about 20 oz), sliced
• 2 Tbsp chopped fresh sage
• Salt and freshly ground pepper to taste
• 3 tart apples (Granny Smith, Jonagold, or Rome would work well), peeled, halved, cored, and sliced ¼-inch thick
• 2 ½ lbs Yukon Gold potatoes (approximately 5), peeled and sliced
• 1 head of radicchio, halved, cored, and sliced into approximately ¼-inch-thick ribbons (Set aside a handful to garnish dish after baking.)
Melt butter in a large saucepan over medium heat. Once melted, stir in the flour until no lumps remain. Cook, stirring often, until the flour turns a golden color, about 5 minutes.
Increase heat to medium-high and slowly whisk in milk until completely incorporated. Bring to a gentle simmer, then reduce heat to medium-low and simmer, stirring often, until the mixture is smooth, silky, and thickened, about 15 minutes.
Remove from heat, stir in cheddar, and season with salt and nutmeg. Set aside.
Prepare the gratin:
Preheat oven to 350°F and spray a 3-quart ceramic or glass casserole with olive oil or rub with butter.
Melt the butter in a medium skillet over medium heat. Add the onions and sage, season with salt and pepper, and cook, tossing or stirring occasionally, until they are soft and fragrant, 8 to 10 minutes.
In a large bowl, combine the onions, apples, potatoes, and radicchio. Stir to combine.
Pour in the béchamel, stirring to distribute sauce, and pour all ingredients into prepared casserole.
Bake, covered with foil, for 45 minutes.
Uncover gratin, increase oven temperature to 400°F, and cook another 15 to 20 minutes until top is golden.
Remove from oven, sprinkle remaining radicchio on top, and let set at least 15 minutes before serving.