Leek, Peas and Mint Soup

A few months ago I went to a vegan restaurant and fell in love with their leek and pea soup. I tried to reconstruct it (and failed as now I see that they used Persian lemons), but it came out delicious. I added a tiny amount of Togarashi to lift it, and kept adding mint leaves until I got the taste I wanted.

Update: This time I added lemon juice, and the result was really great. 

Ingredients >  4 large leeks, white and light green part >  1 large onion, peeled >  2 medium potatoes, peeled >  2 Tbsp vegetable oil (olive or canola) >  Salt and freshly ground black pepper >  400 gm peas (can be frozen) >  1.75 litre vegetable stock >  5 Tbsp mint leaves, chopped >  1/8 tsp chilli powder or Togarashi (completely optional) > 1/2 - 1 squeezed lemon (optional)

Steps 1. Cut each leek in half lengthwise, then slice in 1/2 cm slices. 2. Chop the onion and potatoes into cubes. 3. Heat the oil in a large saucepan. 4. Put in the leeks, onions, and potatoes, add salt and pepper, cover the pot and sweat the vegetables for 15 minutes. 5. Add the chilli (if using), peas and stock, stir and bring to the boil. 6. Turn the heat to its lowest and cook for a further 20 minutes or until the potatoes are cooked. 7. Turn off the heat and stir in the mint, and if used lemon juice. 8. Puree the soup using a hand blender stick. 9. Taste and adjust the seasoning.