Step 1

Preheat the oven to 180c/350f. Prepare a loaf pan with parchment paper or grease with butter. In a large bowl, mix lupin flour, erythritol, baking powder and cinnamon. In another large bowl, add the cream of tartar to the egg whites and whisk into firm peaks.

Step 3

Add the butter, egg yolks and vanilla to the dry ingredients. Add 1/3 of the egg whites. Mix until well combined. Add another 1/3 of egg whites and mix, then add final third being careful not to over mix. Pour the batter into the prepared loaf pan and place in oven for 30 minutes or until golden brown on top. It should have risen and a knife inserted into the middle will come out clean.

Step 5

Remove and leave to cool in the pan for 10 minutes. Then remove from the pan and cool completely on a wire rack.

Step 7

Slice into 12 and enjoy!