Boil the pasta until it's all dente (check the pasta packaging for orientation but cook the pasta for 1-2 minutes less). Don't drain all the pasta water but reserve about 1/2 cup.
Meanwhile, chop the onion, parsley, and garlic. Preheat oven to 360 degrees Fahrenheit (180 degrees Celsius).
Heat oil in a large pan or pot over medium heat and add the diced onion + minced garlic.
Cook for about 3 minutes, then add the spices, pumpkin puree, and reserved pasta water. Stir to combine.
Add plant-based milk + parsley and let simmer for a few minutes.
Stir in the drained pasta.
Taste and adjust seasoning. Add more salt/pepper/herbs to taste if needed. You can add more plant-based milk if you want the pasta bake to be creamier.
Transfer the mixture to a greased baking pan (6×9 or 8×8), and spread it evenly.
Add vegan cheese on top.
Bake at 360 degrees Fahrenheit (180 degrees Celsius) for about 20-25 minutes or until lightly golden brown on top and bubbly.
Garnish with fresh herbs and enjoy immediately. Store leftovers covered in the fridge for up to 3 days.