Bring a large pot of salted water to a boil and add your pasta. Cook according to package directions until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining—this starchy water helps the sauce cling to the noodles beautifully.
While the pasta cooks, heat olive oil and butter in a large skillet over medium heat. Add minced garlic and sauté for 1-2 minutes until fragrant, stirring constantly to prevent browning.
Tear the sage leaves roughly and add them to the garlic, cooking for another 30 seconds to release their essential oils. This step awakens the herbal flavors that define creamy silky pumpkin sage pasta.
Stir in the pumpkin puree, heavy cream, and vegetable broth, whisking until smooth. Add nutmeg, red pepper flakes, salt, and pepper, then simmer for 3-4 minutes to meld the flavors together.
Add the drained pasta directly to the sauce and toss gently. If the sauce seems too thick, add pasta water by the quarter cup until it reaches your desired consistency.
Remove from heat and stir in the grated Parmesan cheese until fully incorporated. Taste and adjust seasonings as needed.
Divide among four bowls and top each serving with toasted pine nuts and an extra sage leaf for garnish.