Heat 1 tablespoon olive oil and 1 tablespoon butter in a deep skillet or Dutch oven over medium heat. Add the diced yellow onion and cook for 4 to 5 minutes until soft and golden. Stir in the minced garlic and cook for 1 minute until fragrant.

Add the cubed butternut squash, 1.5 cups broth, sea salt, black pepper, and nutmeg. Bring to a gentle boil, then cover and simmer over medium-low heat for 12 to 14 minutes, until the squash is completely fork-tender.

While the squash simmers, bring a large pot of salted water to a rolling boil. Add the rigatoni and cook until 1 minute shy of al dente (about 10 minutes). Reserve 1/2 cup of starchy pasta water, then drain the pasta.

Transfer the tender squash and skillet liquid into a high-speed blender (or use an immersion blender right in the skillet). Add the heavy cream and lemon juice. Puree on high for 60 to 90 seconds until completely silky, satin-smooth, and glossy. Pour the sauce back into the warm skillet.

In a small separate skillet, melt 1.5 tablespoons butter over medium heat until foaming and fragrant. Add the fresh whole sage leaves in a single layer and fry for 45 to 60 seconds until dark green and crisp. Immediately transfer the crispy sage with tongs onto a paper towel-lined plate.

Add the drained al dente rigatoni directly into the warm butternut squash sauce over low heat. Toss vigorously for 1 to 2 minutes, splashing in 2 to 3 tablespoons of reserved starchy pasta water to bind the sauce tightly to the pasta ridges.

Remove from heat. Fold in the 1/2 cup of grated microbial parmesan until melted and creamy. Divide into warm shallow bowls. Crown each serving with crispy butter-fried sage leaves, toasted chopped pecans, extra shaved parmesan, and freshly cracked black pepper.