Step 2: Cake Method
In a food processor, pulverize together lemon zest and sugar. (Doing so releases the lemon oils.)
In a mixing bowl, whisk together flour, baking powder and salt. Set aside.
In a mixing bowl, blend softened butter and lemon sugar until thoroughly combined. Add eggs, one at a time and beat until well mixed, occasionally scraping down the sides of the bowl to ensure that everything is well blended.
Add half of flour mixture and mix until just combined. and add half of buttermilk and mix until just combined. Scrape down sides of the bowl. Add remaining half of flour mixture, mix until just combined and then add remaining buttermilk. Mix until just combined.again. At this stage, the less you mix the better for your cake. (too much mixing makes for a tough cake.)
Divide cake into prepared pans. Bake for 40 minutes, or until cake springs back when gently pressed with fingertips. Cool for 20 minutes, then remove cake from pans and cool on wire racks until completely cool.