Chocolate Layer Cake with Chocolate Sour Cream Frosting (Low Carb and Gluten-Free)

Name: Chocolate Layer Cake with Chocolate Sour Cream Frosting (Low Carb and Gluten-Free)
Cuisine: American
Ingredients: 2 1/4 cups almond flour; 3/4 cup cocoa powder; 1/2 cup granulated erythritol (I used Swerve); 1/2 cup vanilla whey protein powder; 1 tbsp instant coffee; 2 tsp baking powder; 1 tsp baking soda; 1 tsp xanthan gum; 1/2 tsp salt; 6 oz Greek yogurt (room temperature); 1/2 cup butter (softened); 5 large eggs (room temperature); 1/4 tsp stevia extract; 2/3 cup almond milk; 4 oz unsweetened chocolate (chopped); 1 1/2 cups sour cream (room temperature); 3 cups powdered erythritol (I used Swerve); 1/4 cup cocoa powder; 1 tsp vanilla extract; 1/8 tsp stevia extract; 1 1/2 tsp xanthan gum