Preheat oven to 180 degrees C (fan forced) and line a small loaf tin with baking paper.
Sift the flour and baking powder into a large bowl. Add the lemon zest and whisk together until thoroughly combined.
Pour in the maple syrup and lemon juice and fold in until just incorporated, with no major lumps remaining. (Try not to overmix)
Pour mixture into the loaf tin and bake for 30-35 minutes or until lightly golden and a skewer inserted into the middle comes out clean. Allow to cool completely before slicing.