Country Vegetable Soup with Open Porridge Bread Chicken Sandwich

1 small onion or leek

225g mixed Irish vegetables (such as celery, carrots, potatoes)

small knob of butter

5g fresh chives (optional)

450ml vegetable stock (made up from a reduced sodium stock cube)

1 teaspoon mayonnaise

2 slices of porridge bread (see separate recipe)

1 small tomato, sliced

80g cooked chicken slices

pinch of snipped fresh chives (optional)

handful soft salad leaves