Quick and easy soup perfect for warming up chilly winter lunchtimes
Put the chopped leeks and potatoes in a large pan with the butter and oil, bring up the heat and stir until the butter has melted. Toss, add the garlic, sea salt, mustard and a few twists of black pepper and then turn the heat right down to sweat for around 5-10 minutes, stirring occasionally so it doesn't catch on the bottom of the pan.
Add the vegetable stock and then bring up to a simmer for around 15 mins until the potatoes are tender. Blitz in a blender until smooth.
Pre-heat the oven to 200C/180C fan/Gas 6. Chop up the bread rolls into 2cm cubes, toss in olive oil, salt, herbs and cheese and then roast in a tin for around 5 minutes until crisp. Sprinkle over the soup just before serving.
Vegetarian? Use a vegetarian-friendly hard cheese instead of Parmesan
Vegan? Use olive oil instead of butter and leave the cheese out of the croutons - they'll still be delicious with plenty of herbs and seasoning.