01 - Preheat oven to 350°F. Line an 8×8-inch baking pan with parchment paper, leaving an overhang for easy removal.
02 - Combine graham cracker crumbs, sugar, melted butter, and salt in a medium bowl. Mix until evenly moistened. Press firmly into the bottom of the prepared pan to form an even crust.
03 - Bake for 8–10 minutes until lightly golden. Remove from oven and let cool slightly.
04 - Whisk together sweetened condensed milk, egg yolks, lime juice, and lime zest until smooth and well combined.
05 - Pour the lime filling over the cooled crust and spread evenly.
06 - Bake for 15 minutes until the filling is just set and barely jiggles in the center.
07 - Remove from oven and cool to room temperature. Refrigerate for at least 1 hour until fully chilled.
08 - Whip heavy cream with powdered sugar until soft peaks form. Spread or pipe over chilled bars and garnish with lime zest.
09 - Lift bars out of the pan using parchment overhang. Cut into squares and serve chilled.