Cyndee's Neiman Marcus Cake

for the cake layer:*

unsalted butter, at room temperature

sugar

extra-large eggs, at room temperature

sour cream, at room temperature

pure vanilla extract

lemon, zested

all-purpose flour

cornstarch

kosher salt

baking soda

*{Instead of making the cake layer from scratch you can also use a vanilla/ yellow box cake (one without pudding) mixed with 1 stick melted butter and 2 beaten eggs (nothing else is added!). This is what my neighbor Cyndee does.}

for the topping:

softened cream cheese

+ ¾ cup powder sugar (1 box)

eggs well beaten