Whisk eggs until smooth in a medium-heavy, 1 quart saucepan. Add sugar and lemon juice, whisking until well mixed. Look slowly over medium-low heat, stirring constantly, until mixture thicken s enough to coat back of wooden spoon (10 - 12 minutes).
Remove pan from heat. Cut butter into tablespoon-size pieces and stir, one piece at a time, into warm mixture until melted and fully absorbed. Stir in lemon zest.
Spoon between the layers of the Sam Houston White Cake. Top with Shiny Chocolate Frosting.
Notes
Lemon Curd is also over pound cake. You can save time by buying your pound cake at the store. I also like to save a little zest to sprinkle on top of individual servings.