We’ve just passed the shortest day of the year here in Melbourne and, somewhat ironically on a day so cold that it broke a 20-year record, I’m writing about salad. But it’s a salad with purpose: I make it as a colourful, healthy break from the traditional, hearty winter fare. A steady diet of slow-cooked meat and root vegetables can, literally and metaphorically, start to weigh me down. As much as I love some cosy domesticity, I can’t survive in an entirely sluggish state until spring. I gots things to do.

There’s no reason it needs to be confined to winter, however. The ingredients all have long seasons, if not year-round. Gorgeous, deeply green cavolo nero and some vivid red cabbage meet in a pan. Meanwhile, cubes of sweet potato – standing in for croutons, really – and some segments of red onion roast in the oven.

Pulling it all together, a revelation if you’ve never tried it with the meaty iron of cavolo nero, a tahini dressing. I make it slightly more lemony than I would normally (more on my ways with tahini here) and it fits perfectly.

The quantities below are nothing more than suggestions. Use what you have, however you want. To line up your timings, the sweet potato and onion take an hour in the oven, while the leafage and cabbage take about 12 minutes. Make the dressing, casually, calmly and with ease, in between.

For 2 by itself, or 4 as a side salad

1 sweet potato (about 2 cups, diced) 1 red onion 1 bunch cavolo nero (about 6 cups, chopped) 1 cup red cabbage, shredded 2 tablespoons olive oil sea salt flakes and freshly ground black pepper

for the dressing: 2 tablespoons tahini paste 2 tablespoons lemon juice

Set your oven to 200°C (400°F). Peel the sweet potato (if you must) and dice it into forkable pieces, about 2cm (about 1 inch) and spread out on a rimmed baking sheet. Slice the red onion in quarters from tip to root, then peel it (much easier this way), then cut each quarter in half again. Wedge these segments among the sweet potato. Drizzle over 1 tablespoon olive oil, tossing to coat lightly. Roast for 1 hour, or until the onion’s tips and some parts of the sweet potato are beginning to scorch.

Meanwhile, make the dressing by stirring the tahini paste and lemon juice together in a small bowl. It will stiffen up at first, but keep stirring and it will come together smoothly. Mix in a couple of teaspoons of water until it thins down to the consistency of heavy cream. Season with salt and pepper. Set aside.

Chop the cavolo nero roughly, stripping the leafy part away from any thicker stems. It will seems like an enormous quantity but it cooks down, so don’t panic. Over medium-low heat, warm the remaining tablespoon of oil in a large pan with a lid that will contain all the cavolo nero.

Toss the leaves in the warming oil as much as you can manage, then put the lid on. Let it cook down for 5 minutes, add the red cabbage and continue cooking, covered, for another 5 minutes or so, until the cavolo nero has collapsed and is very dark but still chewy, and the cabbage has softened but still has a little bite to it.

Take the pan off the heat and add a couple of tablespoons of the tahini dressing. Toss thoroughly, adding more dressing if you think it needs it. Add the sweet potato and red onion segments, tossing briefly again before serving.