Start by prepping your beetroot. Preheat the oven to 200°C. Put the beetroot in a roasting tin with half the olive oil and a sprinkling of salt and pepper. Mix everything together and put in the oven. Roast for 45 minutes to an hour (check with a knife to see if they're done, the beetroot should be very soft).
Shortly before the beetroot is ready heat the second tablespoon of olive oil and the butter over a medium heat. Once the butter has melted add the onion, cook until soft. Add the garlic, cook for two more minutes then add the wine and increase the temperature.
Let it bubble away until the wine has evaporated then add the spaghetti. Pour in the vegetable stock and make sure the spaghetti gets completely covered by the stock. Add salt and pepper to taste. Bring to the boil, put a lid on the pot and cook for 8-10 minutes until the pasta is tender and most of the liquid has been absorbed.
Take the beetroot out of the oven and lightly mash with a fork or potato masher so that you have some mashed and some whole pieces. Add that to the pasta along with the goat's cheese and parmesan. Stir everything through and serve with extra parmesan.