15 g butter
1 heaped tablespoon plain flour
2 hard boiled egg yolks; sieved
300 ml milk
1 tablespoon malt vinegar
pinch salt and white pepper
1/2 teaspoon mustard powder
Yield: 4 servings
Melt the butter and stir in the flour and gently cook for 1 minute. Remove from the heat and mix in the egg yolks to a smooth paste. Gradually add the milk stirring all the time. Return to the heat, keep stirring and simmer for 1 minute. Allow to cool, add the vinegar and seasonings.
Keep covered and refrigerated until required. Keeps for 2-3 days in the refrigerator.