Using a serrated knife, carefully tap and score along the top quarter of each egg, removing and discarding tops. Reserve 2 whole eggs plus 2 yolks. Discard remaining eggs or save for another use. Gently rinse and clean eggshells and place in a medium saucepan of simmering water. Boil shells for 3 minutes. Using tongs, gently remove eggshells and place upside down on paper towels to let dry completely.
In a medium bowl, combine cold cream, crème frâiche, and lemon zest. Beat with a mixer or stand mixer with the whisk attachment until soft peaks form, 2 to 3 minutes. Spoon mixture into a piping bag fitted with a small star tip*. Refrigerate until ready to use.
In a medium heatproof bowl, whisk together reserved whole eggs and yolks, milk, cream, chives, salt, and pepper. Place bowl over a saucepan with simmering water, whisking constantly, until mixture thickens and a digital thermometer registers 180º. Let cool for 5 minutes.
Place dry eggshells in egg cups. Spoon egg custard into shells. Pipe whipped cream mixture onto eggs as desired. Top with caviar and chives as desired. Serve immediately.
Notes
*We used an Ateco #820 decorating tip.
Recipe by Victoria at https://victoriamag.com/caviar-eggs/