double boiler or large bowl, sieve, saucepan, and whisk
Ingredients
½cuplow fat Greek yogurt
½cupsour creamYou could use light, but regular has a better consistency for this sauce.
1 - 2tbsplemon juice
3egg yolks
½tspDijon mustardoptional
pinchsalt
pinchpepper or cayenne
Instructions
In a large heat-resistant bowl, beat yogurt, sour cream, 1 Tbsp lemon juice, and egg yolks well.
Bring 1/2 inch of water in a saucepan or double boiler to a simmer.
Transfer mixture to a double boiler or place the large heat-resistant bowl on the saucepan of barely simmering water (don't let bowl touch water) and heat, stirring frequently, until sauce has thickened. Approx 15 min (sauce will become thinner after about 10 min and then thicken again).
Remove from heat and stir in salt, pepper or cayenne and mustard (if using). Keep warm.