Mix dry ingredients in a bowl, set aside

Roughly chop walnut, set aside

Grate lemon peel, set aside

In a bowl, mix sugar and oil using electric mixer, and mix in half of the grated lemon peel

Then add in half of the flour, top with half of the lettuce, then the rest of the flour, followed with the rest of the lettuce

Add in eggs, one at a time, then fold in chopped walnut

Dump and spread mixture onto pan, bake at preheated 350 F for 25-30 mins

Cool cake to room temperature

Mix icing sugar, lemon juice, the rest of the grated lemon peel, and unsalted butter, then pour mixture on cooled cake

Let icing set before slicing. Best if served the next day!