This is the simpliest version of putting together a loaf cake. Instead of whipping up the eggs and sugar until double in volume and worrying about an emulisfication happening when the butter is added, the butter is melted and whisked in to beaten eggs. Easy!
Start by melting the butter. Set aside to cool while you prepare the rest of the cake.
Preheat your oven to 350F (175C) and line a loaf pan with parchment paper (or grease it with baking spray or butter).
In a large bowl, rub together the sugar and lemon zest to release the oils. Then whisk in the eggs and vanilla extract well, whisking for about 30 seconds.
Mix together the flour, baking powder, and salt in a bowl. Then whisk it into the egg mixture.
Carefully whisk in the cooled melted butter in two additions.
Pour into the prepared pan and bake 45-55 minutes or until golden brown and a toothpick inserted in the middle comes out clean.
After removing it from the oven, let cool several minutes then release it from the pan.
For the glaze, whisk together the lemon juice and powdered sugar then pour over the warm cake.