Moist sheet cake with a subtle lemon flavor, topped with a lemony icing that make this the perfect spring or summer treat.
Grease and flour a sheet pan (no need for parchment paper - non-stick cooking spray and flour sprinkled and tapped around the pan will work). Preheat oven to 350° F.
Sift the flour, sugar, and salt into a large bowl.
In a sauce pan, bring butter, lemon juice, and water to a boil. Pour over the flour mixture and mix on low speed.
In another bowl, add eggs, baking soda, buttermilk, and vanilla. Mix together and add to the flour mixture.
Pour in prepared pan and bake for 20-25 minutes.
Place butter, lemon zest, lemon juice, milk, and vanilla in a saucepan. Melt butter and mix but do not boil. Remove from heat.
In another bowl, place the sugar and pour in the butter mixture. Mix until there are no lumps. Spread over the cake as soon as it is done. Let cool before serving.