• Step 1: Preheat your oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal.
• Step 2: In a medium bowl, combine the graham cracker crumbs and melted butter. Press the mixture firmly into the prepared baking pan to form the crust. Bake for 8 minutes, then let cool completely.
• Step 3: In a separate bowl, whisk together the sweetened condensed milk, egg yolks, and key lime juice until well combined.
• Step 4: Pour the key lime filling over the cooled graham cracker crust and spread it evenly. Bake for 15-18 minutes, or until the center is just set. Allow the bars to cool completely at room temperature, then refrigerate for at least 2 hours (or up to 24 hours).
• Step 5: In a medium bowl, beat the heavy whipping cream and powdered sugar until stiff peaks form. Spread or pipe the whipped cream over the chilled key lime filling.
• Step 6: Refrigerate the bars for an additional 2 hours before cutting and serving. Enjoy!