Prepare gnocchi according to package instructions, reserving ½ cup of the cooking water before draining.
In a large, high-sided skillet, cook bacon over medium-high heat until crispy. Transfer to paper towels to drain.
Retain about 2 ½ tablespoons of bacon fat in the skillet and reduce heat to medium.
Whisk flour into the reserved bacon fat, cooking for approximately 5 minutes to form a roux.
Add minced garlic to the skillet and sauté until aromatic, roughly 30 seconds.
Gradually incorporate whole milk and heavy cream in ½ cup increments, whisking continuously to maintain a smooth texture (you may have a few lumps due to the minced garlic).
Stir in pumpkin puree, ground nutmeg, fresh sage, and season with salt and pepper to taste.
Fold in Parmesan cheese and add the prepared gnocchi into the sauce. If the sauce is overly thick, adjust consistency with reserved pasta water.
Top with crumbled bacon and extra parmesan prior to serving.