Place flour and sugar in the bowl of a food processor. Add butter, and pulse until mixture resembles coarse meal, about 10 seconds. Pulse in 1/2 cup coconut.
In a small bowl, beat together 1/4 cup ice water and egg yolks. With machine running, add liquid to flour mixture in a slow steady stream, until dough just holds together. (You may not need all the liquid.) Do not overprocess.
Turn dough out onto a piece of plastic wrap. Divide in half; flatten into 2 disks. Cover, and chill until firm, at least 1 hour.
In the bowl of an electric mixer, whip the cream to stiff peaks. Transfer to a bowl, and refrigerate. In the bowl of the electric mixer, whip the egg whites to soft peaks. Add sugar in a steady stream while beating. Continue to beat the whites until stiff, 4 to 5 minutes. Whip in lemon zest and juice. Fold in whipped cream until just incorporated (do not overwhip cream). Cover cream filling; chill at least 1 hour, or until ready to use.
Heat the oven to 375 degrees. Roll out half of the dough on a lightly floured surface to 1/8-inch thick. Transfer to a 9-inch pie tin, leaving a 1-inch overhang. Fold under evenly; form decorative edge. Repeat with remaining dough. Prick bottoms of crusts with a fork. Chill until firm, about 30 minutes. Bake crusts until golden, 18 to 20 minutes. Cool completely. While crusts cool, spread remaining 1/2 cup coconut on a baking sheet. Toast until golden, 5 to 7 minutes.
Spread the reserved cream filling in crusts, and refrigerate until ready to serve. Sprinkle with toasted coconut.
Raw eggs should not be used in food prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.