Directions

1. To make the crust, combine the graham cracker crumbs, butter and sugar in a small mixing bowl. Spoon the mixture into 4 dessert cups and gently press down. Set aside.
2. In a mixing bowl, beat the egg yolks, sugar, key lime juice and half of the zest until smooth but not frothy.
3. Sift the cornstarch to the egg mixture and whisk to incorporate.
4. In a saucepan, whisking, slowly bring the milk and vanilla to a low simmer.
5. Whisking, pour ½ cup of the hot milk mixture into the egg mixture to temper.
6. Slowly add the tempered egg mixture to the saucepan with the remaining hot milk mixture and incorporate.
7. Whisking constantly, cook the custard until just thickened (should coat the back of a wooden spoon), about 5 minutes.
8. Remove the custard from the heat and stir in the melted butter or coconut oil. Pour over the crusts.
9. Chill the custard cups for 20-30 minutes and garnish with remaining lime zest to serve.