Step 1

Heat the butter or oil in a large lidded saucepan set over a low–medium heat. Gently fry the onions until soft, keeping the heat low so they don't brown.

Step 2

Stir in the potato and pour in the stock. Cover loosely and bring to the boil. Reduce the heat a little and simmer until the potato is tender (about 10 minutes).

Step 3

Tip in the peas and add 3–4 mint stalks with leaves. Bring back to the boil then remove from the heat. Blend in a food processor or using a hand blender, taste to check the seasoning and add salt and pepper if needed (the stock will be quite salty).

Step 4

Stir in the ham, allow to warm through in the hot soup and then serve, garnished with a few mint leaves.