In a small bowl whisk together egg yolks, sugar, lemon zest, lemon juice and salt. Place the bowl over a double boiler, making sure the water does not touch the bottom of the bowl. Heat over medium, whisking constantly until mixture registers 170°F, about 4 minutes.
Remove from heat and place in the fridge while proceeding.
Whip heavy cream until firm peaks hold. Place in the fridge until ready to use.
Using the same beaters, whip the warm egg yolk mixture until creamy, lite, and cool/room temperature to the touch, about 4 minutes. Stir in Greek yogurt until combined.
Fold whipped cream into egg mixture until combined. Divide evenly into 8-80ml popsicle molds. Freeze for at least 4 hours or overnight. Run warm water over the popsicle molds to loosen slightly before pulling the popsicles out. Popsicles will last for a week if kept covered and in the mold.
-If preferred, remove all popsicles at once and store them in an airtight container for up to one week.