Preheat an oven to 350 F (180 C) and grab a heat-safe ramekin, preferably ceramic. Rub cold butter all over the inside of the ramekin until it leaves behind a thin layer. This helps your souffle rise in the oven. Place the buttered ramekin in your refrigerator to keep cold until later.
Separate the egg(s) and put the whites in a stand mixer with cream of tartar. Whip the egg whites until stiff foam forms. Meanwhile, whisk together almond flour, salt, powdered erythritol, xanthan gum, cinnamon, and chopped dehydrated strawberries in a clean bowl. Whisk the egg yolks, mascarpone cheese, and heavy whipping cream into the dry ingredients.
Once the egg whites are whipped to stiff peaks, fold them into your yolk mixture using a rubber spatula. It’s important to fold carefully until the souffle batter is completely mixed to keep all the little air bubbles in the batter intact. Just as carefully, pour the batter into your prepared ramekin from the refrigerator.
Transfer the ramekin straight to your oven and bake for approximately 20-23 minutes. The souffle will rise high in the oven, so make sure the top doesn’t get too brown and only golden. You may choose to leave the souffle slightly undercooked in the center. Let the souffle cool and settle for just a minute or two after baking before you eat it.