• Sprinkle the powdered gelatin over cold water. Set aside.
• Separate the eggs by placing the yolks in a heat-proof bowl and the whites in a separate bowl.
• Add ½ cup granulated sugar, lime juice and lime zest in to the bowl with the egg yolks. Whisk until combined.
• Place bowl over a saucepan with simmering water (note: bottom of bowl should not touch the water and water should not be boiling). Heat over the simmering water whisking often. Custard will begin to thicken and will reach 180° F when done.
• Add set gelatin to the bowl and stir until gelatin melts.
• Remove bowl from simmering water and allow custard to cool to room temperature.
• Begin whipping egg whites until they are frothy. Slowly pour ¼ cup of granulated sugar into the bowl while continuing to mix. Whip until egg whites reach medium peaks.
• Gently fold the egg whites into the lime custard until no white streaks remain.
• Pour the filling into the graham crust. Place in refrigerator until set (approximately 2 - 3 hours).
• Decorate as desired (e.g. whipped cream, lime slices, etc...)

Pie topping (optional)

• Whip together heavy cream and powdered sugar until medium peaks are formed. Spread on top of pie or use a pastry bag to pie swirls around the pie's edge.