Separate egg yolks from the whites. Set yolks aside. (Refrigerate whites for an egg white omelette at another time).
Put water into bottom saucepan and bring to a boil on medium high heat. Tip: Make sure the water does not the bottom of the top pot.
Place 2nd saucepan on top creating a double boiler.
Divide butter into 3 equal parts.
Place ⅓ of the butter, egg yolks, and lemon juice into the top of the double boiler.
Cook over the hot water stirring constantly, until the butter melts.
Add another ⅓ of the butter and stir until it melts.
Remove the saucepan from the heat and stir in remaining butter and seasonings.
Tips: If sauce is not thick enough continue cooking over the double boiler. If the sauce separates, add 1 to 2 tsp. of boiling water and whisk briskly.
Toss pasta, crawfish and sauce together and serve immediately, warm in a pasta bowl.