4Tbspunsalted butter European butter preferred but not necessary
Instructions
Whisk together 2 eggs, 2 egg yolks, 1/2 cup key lime juice, 1/2 cup sugar, 2 Tbsp cornstarch, 1/2 Tbsp lemon juice, 1 Tbsp lime zest and 1/8 tsp salt in a medium pot. Stir until the cornstarch is dissolved.
Bring the pot to medium-low, stirring constantly for about 6-9 minutes until thickened. It should have a pudding-like consistency.
Remove from heat and immediately stir in butter, stirring until completely melted and smooth.
Place the curd in a fine-mesh sieve and work with a spatula to press the curd through the mesh to remove any lumps.