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1
For the crust:
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Preheat oven to 350F.
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Coat a 9-inch pie pan with cooking spray.
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4
Place egg white, graham cracker crumbs, butter and oil in a medium bowl.
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Blend with your fingertips until thoroughly combined.
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Press the mixture in an even layer on the bottom and sides of the pie plate.
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Bake until lightly browned, about 10 minutes.
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Cool on a wire rack.
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9
For the filling:
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Whisk condensed milk, yogurt, lime zest and juice in a medium bowl.
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11
Stir water and gelatin in a small heatproof cup or bowl.
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Microwave, uncovered, on High until the gelatin has completely dissolved but the liquid is not boiling, 20 to 30 seconds.
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13
(Alternatively, bring 1/2 inch water to a gentle simmer in a small skillet.
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14
Set the bowl with the gelatin mixture in the simmering water until the gelatin has dissolved completely.)
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15
Stir the gelatin mixture, then whisk into the lime mixture.
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16
Set that bowl over a larger bowl of ice water, stirring occasionally, until it begins to thicken, 15 to 20 minutes.
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17
Scrape the filling into the pie shell and refrigerate until chilled and set, at least 4 hours and up to 1 day.
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18
For the meringue and pie:
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19
Position oven rack about 6 inches below the broiler; preheat broiler.
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20
Beat reconstituted egg whites and cream of tartar in a mixing bowl with an electric mixer on medium until soft peaks form.
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21
Gradually add sugar and continue mixing until the egg whites are glossy and hold stiff peaks.
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22
Blend in vanilla.
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23
Spread the meringue over the top of the pie, sealing to the edge of the crust and decoratively swirling on top.
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24
Broil (leaving the oven door ajar and watching very carefully to prevent burning) until the meringue is lightly browned on top, 30 seconds to 1 minute.
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25
Serve garnished with lime slices.
