Lemon Filling

Fills one 2-layer cake servings Prep: 10 m Cook: 15 m Total: 25 m Intermediate
Bake a cake, use this filling recipe and make a memory. The best lemon filling for layer cakes or sweet dough tarts - made with fresh lemon rind, evaporated milk, and eggs for a smooth, creamy texture that’s been filling Cajun cake layers for generations.

Ingredients

  • 1 cup evaporated milk
  • 1 cup sugar
  • 1 egg separated
  • 3 tsp butter
  • rind of 2 lemons
  • 1 tsp lemon flavor
  • 3 tbsp cornstarch

Step-by-Step Instructions

  1. In a medium saucepan, add half of the sugar to the milk while warming over medium heat. Keep warming until it begins to steam.
  2. In a medium bowl combine the remaining sugar and the cornstarch. Beat the egg yolk and then add to the sugar/cornstarch mixture.
  3. Beat the egg white until frothy and add to the mixture.
  4. Add the cornstarch mixture to the warm milk. Cook over medium heat, stirring constantly, until thick and bubbly, about 8-10 minutes.
  5. Once thickened, remove from heat and add the butter, lemon rind, and lemon flavor. Stir until butter is melted and mixture is smooth.
  6. Beat the mixture with a whisk if needed to ensure smoothness and remove any lumps.
  7. Refrigerate 2 to 3 hours for cake filling and spread between cooled layer cake. Also works beautifully in sweet dough tarts.

Common Problems and Solutions

Q: Why is my lemon filling lumpy?

A: Make sure to whisk the cornstarch mixture thoroughly before adding it to the milk, and stir constantly while cooking. If lumps form, use a whisk to beat the mixture smooth before refrigerating.

Q: Can I use fresh lemon juice instead of lemon flavor?

A: Yes, use 2-3 tablespoons of fresh lemon juice, but the flavor will be tangier and less sweet. The lemon extract gives a more traditional filling taste.

Q: Why isn't my filling thickening?

A: Make sure you're cooking over medium heat and stirring constantly. The cornstarch needs to reach a full bubble to activate - this takes 8-10 minutes. If it's still thin after 15 minutes, mix 1 more tablespoon cornstarch with 2 tablespoons cold water and stir in.

Tips and Techniques

The filling will thicken more as it cools, so don’t overcook trying to make it super thick on the stove. It should coat the back of a spoon when done cooking. For the best texture, make sure your cake layers are completely cooled before filling, or the warm filling will make them soggy.

Ingredient Substitutions

  • evaporated milk: whole milk or half-and-half
  • lemon flavor: 2-3 tablespoons fresh lemon juice
  • fresh lemon rind: 1 teaspoon lemon zest or 1/2 teaspoon lemon extract

Equipment Needed

  • Medium saucepan
  • Medium mixing bowl
  • Whisk
  • Grater or zester (for lemon rind)

Historical Context

Lemon fillings like this have been Southern cake standards since the early 1900s, when fresh lemons became more widely available. In Louisiana, they’re especially popular for filling layer cakes for church socials and family gatherings.