Hollandaise sauce is sometimes used with asparagus. (Don't know how it would taste with green beans).
Two recipes for Hollandaise -
(Classic Betty Crocker Cookbook - 1950 version)
Melt in double boiler - 1 stick of butter (1/2 c)
Gradually stir in 4 egg yolks, well beaten. (stir continually)
Gradually stir in 3/4 c boiling water.
Cook over hot water until mixture begins to thicken. Be careful not to cook too long or hard as Hollandaise separates easily.
Remove from heat and add - few grains cayenne pepper, 1/4 tsp salt, 2 Tbsp lemon juice.
Cover and place over hot water until service time (should not stand too long). If sauce starts to curdle, beat vigorously with rotary beater until smooth and creamy. Serve with fish dishes, and borccoli, asparagus, or cauliflower, etc.
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(Silver Palate Cookbook):
3 egg yolks
1-2 Tbsp fresh lemon juice
pinch of salt
2 sticks of melted sweet butter (1/2 lb)
white pepper to taste
Whisk the egg yolks and 1 Tbsp of the lemon juice together in a small heavy saucepan or on top of double boiler. Add a pinch of salt and whisk until sauce is thick and creamy.
Set the pan over very low heat, or over simmering water in the bottom of the double boiler, and begin whisking immediately. Continue to whisk until the egg mixture just begins to thicken. The sign of this is that the wires of the whisk will begin to leave "tracks" in which you can see the bottom of the pan.
Remove pan from the heat and begin to dribble in the melted butter, whisking constantly. Incorporate all the butter but leave the milky residue behind.
Add white pepper to taste and a spoonful or two of additional lemon juice if you like. The sauce will keep, covered, in a warm (not hot) place for at least 30 minutes.
About 1-1/2 cups.