Preheat your oven to 350 F (180 C) and line a small loaf tin with parchment paper.
Add the butter and erythritol to a large mixing bowl. With an electric mixer, beat on high until light and fluffy.
Beat in the eggs, two at a time, until well incorporated. Next, add the vanilla extract and beat on slow until mixed in.
Add the almond flour, baking powder, salt, psyllium husk powder, and xantahn gum, then mix well. The dough will be quite thick but should not dry out.
Spoon the dough into the prepared loaf pan and smooth over the top.
Bake for about 50 minutes or until a toothpick inserted into the middle comes out clean. After 30 minutes, if the top is browning too quickly, cover the loaf with foil to prevent burning.
Remove from the oven and allow to cool completely.