Combine the butternut, water, milk, and garlic and chilli powder ( if using )in a saucepan over medium-high heat. Bring to a boil, reduce heat to medium and until the butternut is tender. This should take about 15 minutes. Allow to cool before pouring into a blender with some milk or cream and blend until smooth.
Pour into a pot and add grated cheese and dried chilli flakes ( if using) Set aside