From the Atkins book:
Cream Sauce - makes 20 tbsp
120g unsalted butter
3 egg yolks
60ml water
60ml double cream
dash of nutmeg (optional)
Place the butter in a bain marie over hot but not boiling water. Add the yolks one at a time, beating constantly with a rotary or hand electric beater. Add the water and cream and continue to beat until the sauce thickens which should take about 7-10mins. Garnish with nutmeg.
0.3g net carbs per 2tbsp
Never made it myself I prefer the cheese sauce, if you do let me know how it turns out!