1. Cook the pasta according to directions until al dente (firm to the bite but not soft). Drain well.

To make the pumpkin filling

1. In a medium bowl, combine the pumpkin puree, ricotta, egg, Parmesan cheese, nutmeg, salt, white pepper and parsley. Mix well and set aside.

To make the white sauce

1. In a small pan, heat milk and stock, or combine and microwave. In a small sauce pan melt the butter over medium heat and add the chopped sage. Saute for 4 minutes. Add the flour and cook for 3 more minutes. Add the hot stock and milk to the butter and flour mixture one third at a time whisking each time. Add salt, pepper, nutmeg and dry mustard. Stir to combine and remove from heat.
2. Heat oven to 375 degrees

To assemble

1. In a medium casserole dish, layer the ingredients as follows: 1/4th of the prepared White Sauce, 1/3rd of the cooked pasta, 1/3rd of the Pumpkin filling and 1/4th of the mozzarella.
2. Repeat these same layers 2 additional times. Then add one last layer of the remaining white sauce and top that with the remaining mozzarella.
3. Bake uncovered in a 375 degree oven for approximately 30-40 minutes or until the top is golden and the dish is heated through and bubbly.