Low-Fat Key Lime Chiffon Pie
Egg whites stand in for the usual whipped cream, and nonfat condensed milk is used, transforming this version into a light chiffon pie that tastes, and looks, deliciously old-fashioned. Key limes are the size of a very large grape. Far more tart than Persian limes, they are hard to find fresh. Bottled Key lime juice, sold in some grocery stores and at specialty-food stores, works just as well.
For the crust:
- 1 1/2 cups graham cracker crumbs, made from reduced-fat cookies (about 12 whole cookies)
- 1/2 tsp. ground ginger
- Pinch of kosher salt
- 1 Tbs. canola oil
- 2 Tbs. nonfat milk
For the filling:
- 1/2 cup fresh or bottled Key lime juice
- 1 Tbs. (1 package) unflavored gelatin
- 3/4 cup sugar
- 3 egg yolks, beaten
- Grated zest of 2 limes (about 1 1/2 Tbs.)
- 1/4 cup nonfat condensed milk
- 4 egg whites, at room temperature
- Pinch of kosher salt
Preheat an oven to 350°F.
To make the crust, in a bowl, stir together the graham cracker crumbs, ginger and salt. Add the canola oil and milk. Starting with a fork, and then using your fingers, work the liquid into the crumbs until the mixture resembles fluffy, moist sand, about 3 minutes. Turn the mixture into a 9-inch pie pan. Using your fingers, press the crust mixture firmly and evenly over the bottom and up the sides of the pan.
Bake the pie crust until it is golden brown, about 8 minutes. Transfer to a wire rack and let cool completely.
To make the filling, pour the lime juice into a small, heavy, nonreactive saucepan. Sprinkle the gelatin over the juice and set aside until the gelatin softens, about 5 minutes. Add 1/4 cup of the sugar, the egg yolks and 1 Tbs. of the zest. Place the pan over medium heat and warm the mixture, whisking constantly, until it thickens to the consistency of a light cream soup and starts to steam, 4 to 5 minutes. To test if it has thickened sufficiently, dip a spoon into the mixture and then run your finger down the back of it; your finger should leave a clear path that does not flow back onto itself. Do not let the mixture boil.
Immediately pour the gelatin mixture into a nonreactive metal or heatproof glass bowl. Mix in the condensed milk, then cover and refrigerate, stirring occasionally with a rubber spatula to prevent the mixture from congealing around the sides of the bowl, until it is the consistency of mayonnaise, 15 to 20 minutes.
Using a stand mixer fitted with the whip attachment or a handheld mixer, beat the egg whites on medium speed until very frothy, about 1 minute. Add the salt and continue beating until soft peaks form, 2 to 3 minutes. Increase the speed to high and begin gradually adding the remaining 1/2 cup sugar, 1 Tbs. at a time, always beating for about 10 seconds to dissolve the addition before adding the next tablespoonful. When all the sugar has been added, continue to beat until the egg whites form stiff peaks, about 2 minutes more.
Using the rubber spatula, gently stir one-fourth of the egg white mixture into the filling, then pour the filling over the remaining egg white mixture and fold gently just until no streaks of white remain. Spread the filling in the cooled pie crust and smooth and level the top with the spatula. Sprinkle the remaining 2 Tbs. grated lime zest over the surface.
Refrigerate the pie until the filling sets, 1 to 2 hours. Chiffon pie is best served the day it is made. Makes one 9-inch pie; serves 8.
Adapted from Williams-Sonoma, Essentials of Healthful Cooking, by Mary Abbott Hess, Dana Jacobi & Marie Simmons (Oxmoor House, 2003).