Preheat your oven to 375 F and grease a 9×13 baking pan.

In a saucepan over medium high heat, melt butter. Then add the flour and whisk together until combined. While whisking, add in the milk and continue mixing until smooth. Add the Parmesan and nutmeg and season with salt and pepper to taste. Now you have a flavorful bechamel sauce! Set aside and cover the pan to keep warm.

In another saucepan, heat the olive oil over medium high heat. Add the minced onion and garlic and cook until softened, stirring often for about 4-5 minutes. Add the sage and saute one minute. Add the pumpkin puree and mix together. Add the ricotta cheese and mix until thoroughly combined, season with salt and pepper to taste. Remove from heat and scoop the mixture into a Ziplock bag. Press all the air out of the bag and seal it closed. Snip one bottom corner off the bag. Set aside for a moment.

Spread about 1/4 of the bechamel in the bottom of the baking pan. Using the Ziplock bag of pumpkin filling, point the cut corner of the bag into the first cannelloni and squeeze the bag of filling until the entire pasta tube is filled. Set the filled cannelloni into the bechamel in the baking pan. Repeat until you are out of filling. Make sure the cannelloni are arranged evenly and then top with the remaining bechamel sauce. Top with mozzarella cheese.

Cover the pan with aluminum foil and bake for 20 minutes then remove foil and bake for another 15-20 minutes. Remove pan from the oven and allow it to cool slightly before cutting into squares and serving!