Prepare all the ingredients.
Preheat oven to 375°F and grease two 10-ounce ramekins with butter.
Dust each with a little bit of granulated Swerve. (You can also make 4 smaller soufflés as these are really rich. Use smaller ramekins 4 to 6 ounces, and watch them carefully because the baking time will be shorter).
In a medium saucepan, whisk together the cream and confectioner's Swerve. Heat over medium and bring to just a boil. Remove from heat and sprinkle with xanthan gum, whisking quickly to combine.
Add chopped chocolate and let sit for a few minutes to melt. Whisk until smooth.
Let cool for a few minutes and whisk in egg yolks and alcohol (or water) and salt.
Beat egg whites and cream of tartar until frothy. Add granular Swerve and beat until whites are thick and glossy and stand up in stiff peaks.
Add about 1/3 of the egg whites to the chocolate and fold in to lighten, Then carefully fold chocolate mixture back into remaining egg whites until just combined.
Divide among prepared ramekins and bake 12 to 14 minutes.
Remove from oven, sprinkle with swerve or dollop with lightly sweetened whipped cream. Serve immediately.