Heat your oven to 200°C/Fan 180°C/Gas 6. Scrub the beetroot and coarsely grate into a bowl. Peel and finely chop the onion.
Crumble the stock cube into a measuring jug. Top up with 750 ml boiling water. Stir to dissolve the stock cube.
Warm 1 tbsp oil in a pan over a medium heat. Add the onion. Season with salt and pepper. Fry for 5 mins till the onion is soft and glossy. Stir often.
Stir the beetroot and rice into the onion. Pour in the vegetable stock. Stir everything together. Bring to the boil, then ladle the risotto into a casserole or ovenproof dish.
Pop a lid on the casserole dish or cover it tightly with foil. Bake for 30 mins till the rice is soft. Remove the lid or foil and cook for another 5-10 mins till the risotto has dried out a little.
While the risotto cooks, tip the salad into a bowl. Whisk 1 tbsp of the red wine vinegar with 1 tbsp oil and some seasoning. Drizzle over the salad.
Finely chop the soft leaves from the dill sprigs. Crumble half the pack of feta (see our tip with what to do with the rest). Taste the risotto and adjust the seasoning. Scatter over the crumbled feta and the remaining dill. Serve with the salad on the side.