Meanwhile, heat the oil in a large saute pan over a medium heat then add the chopped onion. Sizzle for 2 minutes then add the chopped beetroot along with any juice from the beetroot. Cook for a further 2 minutes, then add the thyme and creme fraice.
Simmer for another 2 minutes, stirring often, then season. Drain your pasta and add to the saute pan along with 3 tbsps of the pasta water. Mix well.
To serve, top each bowl with a little crumbled feta and tuck in!