01 - Whisk together eggs, egg yolks, sugar, pink lemon juice, and zest in a medium heatproof bowl until smooth and combined.
02 - Place the bowl over a saucepan of simmering water, ensuring the bowl bottom does not touch the water surface.
03 - Whisk constantly for 8-10 minutes until mixture thickens and coats the back of a spoon, reaching approximately 170°F.
04 - Remove from heat. Whisk in butter pieces one at a time until fully melted and curd achieves silky consistency.
05 - Stir in raspberry juice or food coloring if a deeper pink hue is desired.
06 - Pour mixture through a fine-mesh sieve into a clean bowl to remove zest and any cooked egg particles.
07 - Let cool to room temperature, then transfer to sterilized jars. Refrigerate minimum 2 hours to set. Keeps refrigerated up to 2 weeks.