Preheat oven to 325 degrees F.  Prepare a 4-ounce ramekin for each serving of creme brulee. Place the ramekins in a large cake pan or roasting pan. 

Combine heavy cream, vanilla and half of the erythritol in a medium saucepan. Whisking continuously, bring to a boil. Remove from heat and allow to cool slightly. 

Combine the egg yolks and remaining erythritol in a small bowl.

Temper the egg-erythritol mixture into hot heavy cream mixture by dribbling a small amount of hot cream in a steady stream into the eggs while quickly whisking the two together. This raises the temperature of the egg gradually and cools the cream slightly without cooking the eggs.

Cook until thick enough to coat the back of the spoon.

Fill ramekins 7/8 full. Pour water into the pan so that it comes halfway up the ramekins.   

Transfer to oven and bake until just barely set, approximately 45 minutes.

Remove from oven and allow to cool slightly.