Pumpkin-Stuffed Shells in Parmesan Cheese Sauce

Preheat the oven to 375 degrees F (190 degrees C). Line a baking sheet with parchment paper, waxed paper, or aluminum foil. Grease a 9x13-inch baking dish.

Bring a large pot of salted water to a boil. Add shells and cook, stirring occasionally, until tender yet firm to the bite, about 9 minutes. Drain and set shells aside on the prepared baking sheet.

Whip ricotta cheese, pumpkin, cream cheese, shredded Parmesan cheese, sugar, egg, salt, and pepper together in a large bowl using a hand or stand mixer until creamy. Stuff each shell with filling and replace on the baking sheet.

Melt butter in a large skillet over medium heat. Add garlic and cook for 2 minutes. Whisk in flour until golden and thick to make a roux. Add milk slowly, whisking constantly, followed by half-and-half and grated Parmesan cheese. Whisk until sauce thickens, 3 to 4 minutes. Season cheese sauce with salt and pepper.

Spread just enough cheese sauce into the bottom of the prepared baking dish to cover. Add stuffed shells and pour remaining sauce over.

Bake in the preheated oven until browned, 15 to 20 minutes.