Taken from Stephanie Alexander’s Kitchen Garden Companion.
200g sorrel leaves (about 50-60 leaves), well washed
1 teaspoon Dijon mustard
2 tablespoons pouring cream
2 free range egg yolks
1. Fold each sorrel leaf along its stem line with rough side uppermost, then pull stem up and along leaf. The stem end and central stem will come away, leaving you with two pieces of leaf.
2. Plunge trimmed sorrel leaves into a basin of cold water and give them a good swish.
3. Drop sorrel into a small stainless-steel saucepan with just the water clinging to leaves. Cover and cook over low heat, stirring once, for 2-3 minutes or until it has just collapsed into a greyish-green mass.
4. Tip sorrel into a sieve and press it gently to extract as much liquid as possible.
5. Immediately process sorrel, mustard and cream in food processor for a few seconds to form a smooth puree. Add egg yolks and process again.
6. Scrape puree into a small saucepan and cook over low heat, stirring constantly for 1 minute of until puree has thickened slightly.
7. Remove from heat and serve warm or cold.