Combine melted butter and graham cracker crumbs. Press the crumbs onto the bottom and sides of a 9" pie tin using your hand.
Optional: Bake for 10-15 minutes at 350 degrees F for an extra toasty crust, or leave as is to keep the recipe completely no-bake.
Whisk together egg yolks, yuzu juice, and condensed milk in a saucepan.
Cook on stovetop on medium heat until steaming, continuously whisking.
Turn up the heat to medium-high and continue to whisk until mixture is boiling and has custard-like texture and thickness.
Take off the heat and let cool slightly before pouring into your prepared crust.
Leave in fridge uncovered to set, at least a few hours but preferably overnight.
When ready to serve, whip the heavy cream and sugar on high until stiff peaks form.
Either pipe whipped cream in a fun border around the pie, or simply smooth over the top of the pie with a knife. Serve slices with any leftover whipped cream.