" Carefully brush graham cracker crust with egg white (gently, so crust doesnt crack). Bake in 375 degree oven for 5 min. Remove, let cool. In the meantime, in a large heat-resistant bowl, dissolve gelatin in boiling water. Add fresh lime juice and lime zest to gelatin mixture. With wire whisk, stir in yogurt With wooden spoon, fold in whipped topping. Transfer mixture to prepared, cooled crust. Refrigerate overnight, or at least 2 hours. (Use the crust's plastic cover, flipped over so it makes a dome, as the lid, to keep pie fresh while chilling. Lid also makes this pie easy to transport to a gathering.) Slice and serve into 8 pieces: garnished with thin lime slice, if desired."