Heat your oven to 200°C/Fan 180°C/Gas 6. Break the broccoli into smallish florets. Pop them in a roasting tin. Peel the carrot. Slice it into batons around 1cm thick. Add them to the broccoli.
Trim and peel the beetroot. Halve and slice into wedges around 1 cm thick. Add them to the tin. Drizzle the veg with 2 tsp olive oil. Season. Toss to coat in the oil. Roast for 30 mins till tender and a little charred.
While the veg roast, tip the quinoa into a sieve. Rinse well under cold running water for a few mins. Tip into a pan. Pour in 150ml boiling water. Cover. Bring to the boil.
When the quinoa is boiling, turn the heat down very low. Simmer for 15-20 mins till the quinoa is tender and all the water has been absorbed. If it looks like it’s boiling dry, add a splash more water.
Grate the zest from the lemon. Chop the lemon into wedges for later. Separate 6 large leaves from the cabbage. Spoon the yogurt into a bowl. Sprinkle with a pinch of cumin.
Fill a large pan with water. Bring to the boil. When the water is bubbling, add the cabbage leaves. Simmer for 1-2 mins to just soften the leaves. Lift them out with tongs. Put to one side.
Stir the lemon zest into the quinoa. Season. Divide the quinoa between the cabbage leaves. Fold the top and bottom of the leaves over the filling, then the sides to make parcels. Serve warm with the cumin yogurt and lemon wedges.