Lemon Oreo Cake

Tender Lemon Cake with a Lemon Oreo crust filled with lemon curd and frosted in a delicious lemon Oreo buttercream.

1 1/2 cup unsalted butter (or 3 sticks) left out of the fridge for 15 minutes or so
1 pinch salt
1 Tablespoon pure vanilla
1 teaspoon lemon elixir (or 1/2 teaspoon lemon extract/emulsion - you can add more to taste)
1 teaspoon finely zested lemon you'll want tiny tiny pieces
1/4 cup heavy cream
7-8 cups powdered sugar
4-5 crushed lemon Oreos (small crumbles for easier spreading when adding the buttercream to the cake)
1-2 drops lemon yellow gel coloring

Fresh Lemon Slices Dapped with a napkin or paper towel to remove some of the moisture

Preheat the oven to 325 degrees convection bake (if using traditional bake, you'll have to leave the cakes in a few minutes longer). Prep three 6" cake rounds with a swipe of shortening and dust of flour. Set aside.
In a food processor, pulse the Lemon Oreos and butter until a crust form. Split the crust between the prepared cake rounds and press firmly with the bottom of a glass or bottom of a flat measuring cup. Set aside.
In a large bowl, hand-whisk the lemon zest, lemon juice, buttermilk, sour cream, vanilla, eggs, and oil until it's uniform. Sift in the cake mix and flour (don't overmix). Split the cake batter between the prepared cake rounds.
Bake the rounds for 26-28 minutes, or until the center is finished baking and springs back when touched. Remove from the oven, then let cool in the pan for 1 minute. Carefully flip the cake rounds out onto a wire rack to cool completely, then wrap in plastic wrap and store in the freezer until assembly.

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. The curd should be thickening, and will be thick enough to coat the back of a spoon.
Remove the curd from the heat, and stir in the butter cubes. Stir to combine until the butter has melted. Strain the curd, then discard the zest.
Cover the curd with a light layer of plastic wrap placed directly on top of the surface of the curd, and then store in the fridge until cooled completely.

In a stand mixer fitted with a paddle attachment, whip up the butter until it's light and fluffy. Add in the salt, lemon flavoring (whichever you're using), vanilla, zest, and heavy cream.
Slowly add in the powdered sugar, about 1/2 cup at a time, until it's fully incorporated. Add in a Tablespoon more of heavy cream if needed to thin it out a bit (and more if needed, again). Add in the Oreo pieces and gel coloring. Flip the mixer on the highest speed for about 2 minutes to lighten the texture and color.

On a cake turntable, on a cardboard cake round, spread on a dab of lemon buttercream. Place down the first cake rounds with the crust side up. Spread on a thin layer of buttercream using an offset icing spatula. Pipe a thick dam of buttercream around the outside rim of the cake round. Add in about 1/2 cup lemon curd to the center, then place the next cake round on top. Repeat with the remaining layers.
Crumb coat the cake - leaving the top of the cake exposed (crust side up). Freeze for 5 minutes.
Add on a final layer of buttercream using a straight icing spatula and use a cake scraper to make smooth sides. Leave the top edge unfinished for a rustic look. Add on the lemon slices along the sides.
When serving, slice the cake with a hot sharp knife for the cleanest slices. Remove the lemon slice garnishes before serving.