Heat your oven to 180°C/Fan 160°C/Gas Mark 4. Peel and finely slice one garlic clove. Pull the leaves from the rosemary. Using a small sharp knife, make small holes in the pork fillet. Push a slice of garlic and a couple of rosemary leaves into each incision.
Place the pork fillet on a baking tray. Rub with 1 tbsp olive oil. Season. Place in the oven and cook for 30-35 mins. Check the pork is cooked through by piercing with a sharp knife. The juices should run clear. Remove from the oven and leave to rest, covered.
While the pork is cooking, peel and dice your onion. Peel and crush the garlic. Heat 1 tbsp olive oil in a large frying pan. Gently fry the onion for 6 mins until soft. Add the garlic and cook for 2 mins. Boil the kettle.
Peel and coarsely grate the beetroot. Rinse the quinoa under cold water then add to the pan. Pour 400ml hot water in to a jug. Add a ladleful at a time, stirring until the water is absorbed before adding another.
Zest the lemon and squeeze juice from half. Add to the crème fraiche. Season. Mix well.
After 15 mins, the quinoa should be nearly cooked. Add the grated beetroot and cook for a further 5 mins. Fold through the lemon crème fraiche. Finally stir through the baby spinach and cook until just wilted.
Slice the pork fillet at an angle. Spoon the ruby quinoa on to two plates. Top with the sliced pork fillet and serve with lemon wedges for squeezing.