
A Luscious Lemon Bar Sheet Cake with a zesty homemade Lemon Curd, Shortbread Crust on bottom, and a tasty lemon buttercream.
Prep a 9x13 sheet pan with a swipe of shortening and dust of flour to prevent sticking. Preheat the oven to 325 degrees. Set aside.
In a medium saucepan over medium heat, stir together the yolks, sugar, juice, and zest. Whisk together as the mixture begins to thicken, about 6 minutes. Curd should be thickening, and will be thick enough to coat the back of a spoon.
In a stand mixer fitted with a paddle attachment, whip up butter for about a minute until light and fluffy. Scrape down the sides of the bowl.
Add 1 1/2 cups of buttercream to a piping bag fitted with a 1M piping tip, set aside.