Sorrel soup

1 onion

1 jar sorrel (300g)

4 jars water
1 potato

stock cube or Polish soup seasoning

Sweat the chopped onion in a bit of oil. Tip in the sorrel and wash it down with 4 jars of water. Bring to simmer and add diced potatoes. Simmer until potatoes are tender, then blitz and correct seasoning. Garnish with a dollop of thick yogurt and a quartered hardboiled egg.