Put the grated beetroot, pasta, thyme leaves, garlic and vinegar into a medium lidded pan with 1 teaspoon of sea salt, the 2 tablespoons of oil and 850ml water.
Crumble in the stock cube or add the powder. Place the pan over a high heat, cover with a lid and bring to the boil, then simmer for 10 minutes until the pasta is cooked and all the water has been absorbed.
Stir it every minute or so to make sure that the pasta doesn’t catch on the bottom of the pan. If the orzo looks a little thick (you want it to be the consistency of risotto) add a little more hot water.
Spoon onto warm plates and finish with some orange zest, peppery leaves, a crumbling of feta (if using), some toasted nuts and a good drizzle of oil.