Preheat the oven to 180 Deg C/ 400 Deg F.
Grease a 6 inch Bundt Pan/Round Tin/ Square Tin with oil.
Lighlty dust it with flour and shake off the excess
In a small bowl, add in 1 tablespoon of flour and mixed peels.
Coat the peels evenly with the flour mix.
In a separate wide bowl sift in the dry ingredients. That is Whole wheat flour, baking powder, baking soda, and salt.
Add in the dark brown sugar to the dry mix. Making sure that it is lump-free.
Add the mixed peels to the dry ingredients ad give it a nice mix.
Now add the lemon zest and mix it again.
Now in a separate bowl add in lukewarm water, lemon juice, vanilla extract, and oil.
Add the wet ingredients to the dry mix and mix everything until well incorporated.
Pour the batter in the prepared baking tin.
Bake in a preheated oven for 30-40 minutes.
The cake is done when a toothpick inserted comes out clean.
Let the cake cool completely in the pan, before removing and cutting.