Preheat your oven to 350 degrees. In the bowl of a food processor, pulse the gingersnap cookies and the sugar until they are the consistency of sand. Alternatively, place the cookies in a large ziploc bag and crush them with a rolling pin.
Add the melted butter and combine well.
Press into a 9” pie plate, making sure the crumbs are evenly distributed along the bottom and sides.
Bake at 350 degrees for 10 minutes. Remove from oven but keep the oven on and set at 350 degrees.
To make the pie filling, whisk together the key lime juice, sweetened condensed milk, lime zest and egg yolks until fully combined. Pour into pie shell and bake for 25 minutes at 350 degrees. The top should jiggle slightly when done.
Cook on wire rack fully before transferring to fridge to chill at least six hours or overnight.
Serve with whipped cream if desired.
