Americana Key Lime Pie

This key lime pie takes the chiffon route instead of the classic sweetened-condensed-milk route, which gives the filling a cool, mousse-like lightness instead of the dense, almost custard-like body of a Florida-style key lime. The combination of gelatin, beaten egg whites, and folded whipped cream creates layers of air that float over the baked shell.

The freshly squeezed lime juice does the entire flavor work. Half a cup is enough to give every bite that puckery citrus snap. Don’t skip the lime zest, it adds a fragrance the juice alone can’t deliver. The drop of green food coloring is purely visual, the natural color is a barely-tinted pale yellow.

Folding the partially-set gelatin mixture into the egg whites at the right stage is the crucial step. The gelatin should mound slightly when dropped from a spoon. That’s the texture window. Too liquid and the pie collapses, too set and it’ll never fold smoothly into the whites.

Pro Tips

• Use real key limes if you can find them, Persian limes work fine but key limes have a more aromatic, slightly bitter character
• Bring the egg yolks to room temperature before cooking, cold yolks shock the gelatin and can create lumps
• Beat the egg whites in a spotlessly clean bowl with no trace of yolk or oil, fat in the whites prevents them from reaching stiff peaks
• Don’t overfold once the gelatin and whites combine, gentle figure-eight motions keep the air in
• The pie needs at least 4 hours in the fridge to set, overnight is better

Variations

• Top with a meringue made from the leftover egg whites instead of whipped cream for a different texture
• Use a graham cracker crust instead of pastry for more traditional key lime pie character
• Substitute lemon juice and zest for the lime to make a chiffon lemon pie