Preheat your oven to 200°C/Fan 180°C/Gas 5. Scrub and chop the sweet potatoes into 2cm chunks. Quarter the tomatoes. Slice the onion. Scatter all 3 onto a baking tray. Drizzle over 1 tbsp olive oil and add some salt and pepper. Toss together. Place the garlic cloves on the baking tray.

Slide into the oven for 30 mins, tossing the veg half way through cooking. The sweet potato should be tender and lightly caramelised at the edges. The tomatoes and onions should be soft.

While the veg roast, zest and juice the lime into a bowl. Finely chop the coriander stalks and add those. Mix in the yogurt and add a good pinch of salt and pepper.

After 30 mins, remove the veg from the oven. Remove the garlic cloves from the tray and place on a chopping board. Dust the veg with 1 tbsp garam masala and gently turn over a couple of times. Slide back into the oven for 5 mins.

Using the back of a knife, squeeze the roasted garlic cloves from their papery skins. Crush and finely chop the flesh. Add it to the yogurt and stir.

Arrange the watercress on a serving platter or divide between a couple of plates. Tumble over the garam masala roasted veg. Dot over the garlic yogurt and tear over the coriander leaves to serve.