Preheat oven to 350 degrees. Line an 8 x 8 inch cake pan with parchment paper.
In a large mixing bowl whisk together almond flour, coconut flour, brown Swerve, salt, baking powder until fully combined or until no lumps. May need to use fingers to break up the lumps in the brown Swerve
Add eggs and whisk until fully combined and no dry ingredients are left
Add sour cream and whisk until fully combined and the batter is smooth
Add melted and cooled butter. Whisk until fully combined and completely smooth
Scrape down the sides of the bowl if needed and pour the batter into the prepared cake pan. Use a spatula an spread the batter evenly in the pan
Bake 20-25 minutes or until golden and a tester comes out clean. The bread will be a little soft but will firm up as it cools
Allow the bread to cool in the pan for at least 10 minutes or until cool enough to cut without it falling apart
After the bread has cooled cut the bread into the desired pieces. The bread will still be warm so cut carefully to avoid falling apart. Serve warm with butter or let cool completely and store at room temperature in an airtight container.