3 egg yolks
2 tbsp. fresh lemon juice
1/4 tsp. salt
1/8 tsp. cayenne or white pepper
1 tbsp. minced fresh parsley (optional)
1/2 c. unsalted butter, melted and sizzling hot

Combine yolks, lemon juice, salt, cayenne and parsley (if desired) in blender or food processor and mix 5 seconds. With machine running, pour hot butter into egg mixture in slow steady stream (it should take about 15 seconds). If sauce is too thick, stir in 1-2 tablespoons hot water.