In a small bowl, add the sour cream, egg, apple cider vinegar, vanilla extract and lemon zest. Mix with a fork until full blended.
In the bowl of a food processor, add the almond flour, flaxseed meal, coconut flour, sugar, baking powder, xanthan gum and salt. Pulse a few times to mix the dry ingredients together.
Cut the butter into chunks and add it to the food processor - pulse a few more times until the mixture resembles crumbs.
Add the sour cream mixture and pulse again a few times to full mix.
Scrape the batter out of the food processor and into a medium size bowl. Let rest for 30 minutes.
Preheat oven to 450 F. Line a cookie sheet with a sheet of parchment paper.
Using a rubber spatula, gently fold in the blackberries.
Turn the dough onto the cookie sheet and pat into a 6 ½ inch circle.
Using a sharp knife, cut the disk into 6 slices.
Bake for 20 minutes. Remove from the oven and separate the scones - slice again if needed. Return to oven to bake for 7 -10 more minutes. Cover with foil if they get too brown.
Remove and let cool. Prepare glaze.
For the glaze
In a small bowl, add the powdered sugar and lemon juice. Mix with a fork until drizzle consistency. Drizzle over cooled scones.
Notes
Make sure ingredients are at room temperature.
Let dough rest the full 30 minutes for the flour to hydrate.
Scrape batter into a medium bowl to fold in the blackberries otherwise the food processor blades will get in the way.
Bake for 20 minutes, then separate them. Return to the oven to finish baking. Cover with foil if they're getting too brown.