Adapted from Classic Home Desserts by Richard Sax. If you don't have key limes, you can substitute with regular lime juice. I found the best jars for these are little 4 oz. canning jars. You can also pop them in the freezer with the lid on, and either let them thaw in the picnic basket or, on especially hot days, eat them frozen.
Ingredients
½ c. milk
¾ packet gelatin
2 egg yolks
½ c. key lime juice (12 limes)
¼ c. sugar, divided
½ cup nonfat vanilla Greek yogurt
2 egg whites
2 oz. Trader Joe's cats' cookies (these are easily replaced with gluten free cookies to make these gluten free)
6 4-oz. canning jars
Instructions
Sprinkle the gelatin over the milk, and wait a few minutes until the gelatin has softened.. Remove 1 Tablespoon of the milk gelatin mixture and set aside. Heat remainder of milk mixture to nearly boiling.
Mix the reserved milk with egg yolks and 2 Tablespoons sugar and beat until combined. Add the hot milk mixture, then return mixture to stovetop and heat until thickened enough to coat a spoon. Add yogurt and lime juice. Chill until cold, stirring periodically.
Meanwhile crush the cats cookies until fine, and divide the crumbs among the jars.
Beat the egg whites with remaining 2 T sugar until stiff. Fold the egg whites into the chilled lime mixture, then pour the mixture into the jars on top of the crumbs.
Cap with the jar lids and chill until solid. Serve topped with whipped cream.
Recipe by The Domestic Front at http://www.thedomesticfront.com/mini-key-lime-yogurt-pies-in-jars/