In a large mixing bowl, use an electric mixer on medium-high speed to whip 2 cups of heavy whipping cream until stiff peaks form.

In another bowl, combine one 14-ounce can of sweetened condensed milk, ½ cup of freshly squeezed key lime juice, the zest of one lime, 1 teaspoon of vanilla extract, and a pinch of salt. Mix until smooth.

Gently incorporate the whipped cream into the key lime mixture in two or three batches, preserving the airy texture.

Fold in ¾ cup of crushed graham crackers and reserve some for topping.

Pour the mixture into a freezer-safe container, smoothing the top and sprinkling the reserved graham cracker crumbs.

Cover and freeze for at least 6 hours or overnight.

Before serving, let the ice cream soften for 5 minutes. Serve and enjoy with optional lime zest.