Schav is my go-to recipe for a cool summer refresher. I serve it in mugs to sip outdoors on the deck. My Russian mother made it all summer when I was a child. If fresh sorrel leaves aren't available, substitute fresh spinach and up the lemon to taste. —Lily Kayte
In a large saucepan or Dutch oven, melt butter and sauté sorrel and onions for about 10 minutes or until sorrel is wilted and onions are translucent. Add water or stock and salt. Bring to a boil. Reduce heat and simmer 30 minutes.
Remove from heat and stir in sugar and lemon juice a little at a time, tasting after each addition of lemon juice, until desired tartness is achieved.
Temper the egg yolks with a few tablespoons of hot soup, then stir the tempered egg yolks back into soup. Turn heat on and cook until slightly thickened and simmering but do not allow it to boil as the eggs will curdle. Cool, cover and chill .
Serve with sour cream stirred in.