Preheat your oven to 220°C/200°C fan/gas mark 7.

Bring a large saucepan of water with ½ tsp salt to the boil for the potatoes. Chop the potatoes into 2cm chunks (peel first if you prefer).

When boiling, add the potatoes to the water and cook until you can easily slip a knife through, 15-20 mins. 

In the meantime, halve any large cauliflower florets. 

Pop the cauliflower onto a baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. Spread them out in a single layer.

When the oven is hot, roast on the top shelf until golden brown and tender, 15-20 mins. Turn halfway through.

While everything cooks, peel and grate the garlic (or use a garlic press). Drain and rinse the lentils in a sieve. Grate the Cheddar.

Finely chop the chives (use scissors if easier).

Heat a drizzle of oil in a large frying pan on high heat.

When hot, add the mushrooms to the pan. Season with salt and pepper and fry, stirring occasionally, until browned, 5-6 mins.

Add the garlic and fry for 1 min more. 

Stir through the passata, lentils, vegetable stock paste, sugar and water for the sauce (see pantry for both amounts). Bring up to a boil, then lower to a simmer. Cook until thickened slightly, 5-6 mins. 

Once the potatoes are cooked, drain in a colander and return to the pan, off the heat. Add a knob of butter and a splash of milk (if you have any) and mash until smooth. Season with salt and pepper and fold through the chives. Cover with a lid to keep warm.

Meanwhile, stir the harissa through the sauce and remove from the heat.

Once the cauliflower has finished roasting, change your oven setting to grill and set it to its highest temperature. 

Stir the cauliflower into the sauce, then pour it into an appropriately sized ovenproof dish. Top with the mashed potatoes and sprinkle over the Cheddar.

Once the grill is hot, grill the pie until golden, 4-5 mins. TIP: Place your baking dish onto a baking tray to catch any drips. 

Share your harissa cauliflower and lentil pie between your serving plates.