Preheat oven to 400F/200C

Peel both sweet and white potatoes and cube them. Cut sweet potatoes in large cubes as they will cook faster than the white ones.

Slice red onion, red pepper and garlic.

Toss everything in a large roasting pan with harissa paste and olive oil. The vegetables should be in one layer and not too crowded so they roast instead of steam. No salt added as halloumi cheese is very salty.

Roast in the oven for 35 minutes.

A few minutes before the potatoes are done, slice halloumi as thinly as possible.

Take the potatoes out of the oven and test for doneness.

Turn the oven to grill/broil.

Scatter halloumi all over the potatoes and broil for a couple of minutes until the cheese will start to turn colour. (Halloumi doesn't melt like cheddar or mozzarella)