You’ll need graham crackers, butter, sugar, egg yolks, sweetened condensed milk, and fresh Key lime juice (or bottled if needed).
Crush graham crackers, mix with melted butter and sugar, then press into a pie pan. Bake at 350°F (175°C) for 10 minutes.
Remove crust from oven and let it cool slightly. This helps it firm up and prevents sogginess when adding the filling.
Whisk egg yolks, sweetened condensed milk, and Key lime juice until smooth and thickened. The acidity helps the filling set.
Pour the filling into the cooled crust and spread evenly. Tap gently to remove air bubbles.
Bake at 350°F (175°C) for 15–18 minutes. The edges should be set but the center slightly jiggly — it will firm up when chilled.
Let the pie cool to room temperature, then refrigerate for at least 3 hours to fully set and develop flavor.