To prepare a spaghetti with aubergine, butternut squash and prawns recipe, you will first need to prepare the squash. Peel and slice the auberine and cut it into small cubes. Add the cubed squash to the boiling water and cook until tender, about 10 minutes. Drain the pasta and place it in the saucepan with the vegetable stock. Bring the mixture to boil, then reduce the heat to medium-low and simmer until the spaghetti is al dente. Remove the pan from heat and add the salt and pepper to taste. Serve with sour cream and grated Parmesan cheese.