01 - In a medium heatproof bowl, whisk together the eggs, egg yolks, sugar, pink lemon juice, and zest until smooth and well combined.
02 - Place the bowl over a saucepan of simmering water, ensuring the bottom does not touch the water to create a gentle double boiler.
03 - Cook, whisking constantly, for 8–10 minutes until the mixture thickens and coats the back of a spoon (reaches about 170°F).
04 - Remove from heat. Whisk in the butter, one piece at a time, until fully melted and the curd becomes silky and emulsified.
05 - If desired, stir in raspberry juice or natural pink food coloring to enhance the pink color to your preference.
06 - Strain the curd through a fine-mesh sieve into a clean bowl to remove zest and any cooked egg bits for a smooth texture.
07 - Let cool, then transfer to sterilized jars. Refrigerate for at least 2 hours to set properly. Keeps up to 2 weeks chilled.