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