Boil the Pasta: Bring a large 5-quart pot of water to a rolling boil over high heat. Add 1 tablespoon kosher salt. Drop in 12 ounces of rigatoni pasta and cook until 1 minute shy of al dente according to package instructions (about 10 to 11 minutes). Before draining, carefully ladle out 1 full cup of starchy pasta water and set aside. Drain the pasta and keep warm.

Crisp the Sage Leaves: While the pasta boils, place a large wide skillet or Dutch oven over medium heat. Melt 1 tablespoon of butter and 1 tablespoon olive oil. Once bubbling, add the whole sage leaves in a single layer and fry for 60 to 90 seconds until dark green and crisp. Use tongs to transfer the crispy leaves to a paper towel-lined plate, leaving the infused aromatic oil in the pan.

Sauté the Aromatics: Add the remaining 2 tablespoons of butter to the skillet. Stir in the finely minced shallot and cook for 2 to 3 minutes over medium-low heat until soft and translucent. Add the minced garlic and cook for 60 seconds until fragrant, taking care not to burn the garlic.

Build the Pumpkin Cream Sauce: Add 1 cup pure pumpkin puree, 1/2 cup vegetable broth, 1/4 teaspoon grated nutmeg, 1/2 teaspoon sea salt, black pepper, and optional red pepper flakes to the skillet. Whisk well to combine and let the mixture simmer gently for 3 to 4 minutes until hot and smooth. Reduce heat to low and stir in 1/2 cup room-temperature heavy cream until the sauce turns glossy and velvety.

Toss & Emulsify: Add the drained cooked rigatoni directly into the skillet with the pumpkin sauce. Pour in 1/3 cup of the reserved starchy pasta cooking water and toss vigorously with tongs for 1 to 2 minutes over low heat. Sprinkle in 1/2 cup grated Parmesan cheese and toss until the cheese melts and the sauce clings tightly to every ridge of the pasta. If the sauce seems too thick, splash in an extra tablespoon or two of pasta water until silky.

Garnish & Serve: Taste and adjust with a pinch of sea salt or black pepper if desired. Divide the steaming pasta into warm ceramic bowls. Top each bowl with the reserved crispy fried sage leaves, a light dusting of extra parmesan, and freshly cracked black pepper. Serve warm immediately.