Heat 2 tbsp of the oil in a large, deep saucepan over medium-high heat. Stir in the onion and a pinch of salt and cook for 6-8 mins until softened around the edges. Stir in the garlic and potatoes and cook for 2-3 mins until fragrant. Pour over the stock and bring to a simmer. Let it bubble away for 10-15 mins until the potatoes are just tender then pour in the crème fraîche, greens and frozen peas. Bring back to a simmer and cook for 4-5 mins until the greens have all wilted and the crème fraîche has dissolved. Stir in the herbs and using a hand blender, blitz until smooth. Season.

Meanwhile, heat the remaining oil in a frying pan. Stir in the harissa and honey and let it melt. Pour into a bowl, then add the halloumi to the pan and brown all over, shuffling the pan occasionally for 4-5 mins. Return the harissa mixture to the pan and stir quickly to coat the halloumi. Scatter the halloumi croutons on top of the soup and serve the sourdough on the side.