Line 18 muffin cups with paper liners, and place one Sandies shortbread cookie in the bottom of each. Preheat oven to 325 degrees.

With a zester, remove 1 tablespoon zest from the lime rinds, and then squeeze ½ cup juice from limes.

Whisk sweetened condensed milk with yolks. Add juice and zest, and let sit until thickened. (about 5 minutes)

Scoop 2 tablespoons of lime filling into each cookie lined cup.

Bake at 325 degrees for 10 minutes until the centers are set, but still wiggle when shaken.

Cool completely, then refrigerate overnight.

Serve with whipped cream.