Preheat the oven to 350º F/ 180º C. Line a medium loaf pan with parchment paper and grease it well under the paper.

In a bowl combine the coconut flour with the baking powder and stir to blend.

In a large mixing bowl whisk together the eggs with the erythritol for 2 minutes. Add the oil and the lemon zest/ extract and whisk again to combine.

Whisk in also the sour cream.

Fold in the coconut flour mixture and then the almond flour. Make sure no lumps remain!

Pour the batter into the prepared pan. Bake for about 40 minutes or until the top is golden brown and a wooden skewer inserted in the middle of the cake comes out clean. If the top has darkened while the inside is still not baked, cover with parchment paper for the rest of the baking.

Let the cake cool in the pan for at least 30 minutes before removing it and serving it.

Optionally sprinkle with powdered xylitol/ erythritol before serving.