In separate bowl from mixer, mix together almond flour, salt, baking powder, baking soda, sifted cocoa powder, xanthan gum.
In mixer, cream butter and Swerve.
Add eggs one at a time.
Put sour cream in measuring cup. Fill with milk up to 1/2 cup mark. (I use Fairlife, which is low-carb. You can use heavy cream if desired). This makes a buttermilk.
Add food coloring to buttermilk mixture.
Add almond flour mixture to sugar/egg mixture alternating with buttermilk mixture.
Add vinegar at the end.
Bake immediately for 15 minutes at 350 F./ 180 C..
Cool and frost with cream cheese frosting found here.