Poulette Sauce

This lemony sauce is great on steamed green beans or broccoli.

Ingredients
25g Butter
1 egg Yoke
Dessert spoon flour
1/2 tspn mixed herbs
1 tspn chicken stock (or 1/2 - 3/4 cup of chicken stock)
1/2 - 3/4 cup of water
Juice of 1 lemon

Method
In a saucepan, melt butter and add flour while whisking (to avoid lumps)
Put chicken stock into water, stir and add butter, flour mix
Add herbs
Take off heat and add yoke and lemon juice
Stir off the heat
Gently heat but don't let it boil