Key Lime Tarts

Directions

1. 1
   Empty the digestives into a large bowl. Using the heel of a glass, crush the digestives until you achieve the consistency of sand. (I promise, it doesn't take more than 5 minutes).
2. 2
   Cut the butter into slices, and then use your fingers to incorporate into the crumbled digestives. Add the sugar, and mix with your fingers until you achieve the texture of wet sand. Spoon the mixture into tart shells, and press into a crust.
3. 3
   Empty the sweetened condensed milk into a medium bowl. Add the key lime juice, a bit at a time. (If you can't find fresh key limes, use Nellie and Joe's Key West Juice from the supermarket). Mix in lime and grapefruit zest, then mix in the egg yolks; stir until just incorporated.
4. 4
   Pour the filling into the tart shells and cook at 350F for 12 minutes. When they come out of the oven, allow them to cool, and then chill before serving.
5. 5
   Optional: Serve with freshly whipped cream.