Preheat oven to 350ºF.
In a medium-sized mixing bowl, beat together the butter and coconut sugar.
Add the eggs and vanilla extract and continue to mix.
In a separate mixing, blend the baking soda, salt, almond flour and arrowroot flour together.
Combine the dry ingredients with the wet ingredients. Gradually add the sour cream, adding a little bit at a time.
In a separate small mixing bowl, stir together the chopped nuts, coconut sugar and cinnamon for the topping and filling.
Generously grease a fluted tube pan or a springform pan with butter. Use a pastry brush to make sure you get every single small corner and ridge. This will prevent the cake from sticking.
Spread a small amount of the topping mixture into the bottom of the pan.
Pour about ⅓ of the batter into the pan, and smooth.
Sprinkle ⅓ of the leftover topping onto the batter.
Do this two more times ending with the topping which will be the bottom of the cake.
Bake at 350ºF for 50-55 minutes, or until a long wooden pick comes out clean.
When the cake is done, allow it to completely cool on a wire rack.
After it has cooled, remove from the pan and place it on a cake stand with the fluted side up.