For an extra layer of flavor, try roasting a few cloves of garlic alongside the butternut squash. Squeeze the roasted garlic into the puree for a delicious depth. If you prefer a vegan version of this dish, substitute the chicken stock with vegetable broth, the milk with plant-based milk (such as almond or soy milk), and the Cheddar and Parmesan cheeses with vegan cheese alternatives. Adjust the amount of cayenne pepper according to your spice preference. A pinch of red pepper flakes can also be added for an extra kick. To prevent the butternut squash from drying out during roasting, you can brush the cut sides with a little olive oil before placing them on the baking sheet.