To make the caramel:

In a saucepan combine the water, Xylitol and butter, Bring to a boil, stir frequently and continue cooking for 7-9 minutes, until 1.2 of the water evaporated and the mixture thickens.

Divide between 3 6 oz ramekins. Place in a baking dish and fill the baking dish with hot water, covering 1/2 of the height of the ramekins.

Custard:

Whisk together the eggs and egg yolks.

Combine the sweetener and heavy cream, vanilla extract and pinch of salt and whisk to combine. Add the eggs and whisk until incorporated.

Strain the mixture into the ramekins.

Place ramekins in a larger baking dish and pour hot water inside the dish, covering the ramekins half way through.

Bake at 350 F (180 C ) for 25-35 min, until the custard is set around the edges and wiggly in the middle.