Please check if the baking powder or flour is expired prior to starting.

Preheat the oven to 350F (180C). Line a loaf pan with parchment paper and spray with baking spray. You can use a bigger size pan as well, but the cake will be larger and thinner, so you may need to adjust the baking time.

Wash the lemon really well. You can also soak it in some vinegar + water to draw out any impurities. Cut into slices or quarters.

Add all of the ingredients to a high-power blender, starting with the wet ingredients. Be sure to add the wet ingredients first so that the blender doesn't get stuck. Blend for 15-20 seconds or until a thick pourable batter forms. Do NOT over-blend as this will break down the pith and result in a very bitter cake.

Pour the batter into the lined pan and bake at 350F (180C) on the middle rack for 45 to 50 minutes or until a toothpick comes out clean 2 inches from the side.

Remove the cake from the oven and let it cool for 10 minutes. Take the cake out of the loaf pan once it has cooled, and optionally top it with the lemon glaze. You can also enjoy this cake on its own or with a simple dusting of powdered sugar on top.

Combine the powdered sugar and lemon juice until you reach your desired consistency. Pour the glaze over the cake and enjoy!