Tip the beetroot and onion into a shallow roasting tin big enough to hold them in one layer, add the olive oil, cumin and half a teaspoon of flaky sea salt, toss to coat, then roast for 30 minutes.
Whisk the extra-virgin olive oil, lemon juice and remaining teaspoon of sea salt, until emulsified, then use this to dress the lentils.
2 heaped tsp pumpkin seeds, roughly chopped.
Meanwhile, mix the lentils, spinach, pomegranate seeds and walnuts in a large bowl.
1 red onion, peeled and roughly chopped.
