Crust
1 1/2 cups graham cracker or animal cracker (can do GF) crumbs (11 crackers?)
2 T sugar
1/2 t ground ginger
1/4 t salt
5 T unsalted butter
Filling
1 1/4 cups sugar
1/3 cup cornstarch
2 T grated grapefruit zest
1 1/4 cups fresh grapefruit juice (2 grapefruit)
1/2 cup water
4 egg yolks
4 T unsalted butter
Meringue
4 egg whites
1/4 t cream of tartar
1/2 cup sugar
Crust: Preheat oven to 350 degrees. Melt the butter for the crust. Combine crumbs, sugar, ginger, salt, and butter, and press into pie pan or muffin pan liners. Bake until set and light brown, about 10 minutes. Allow to cool.
Filling: Whisk cornstarch and water together until the cornstarch dissolves before heating. Combine the cornstarch solution, the sugar, and grapefruit juice together in a saucepan, whisking in the egg yolks one at a time over medium heat. Mix in the 4 T of butter and the zest as the filling begins to thicken, stirring constantly. Pour the filling into the crust(s), and chill for at least 1 hour for tarts and 3 hours for a pie.
Meringue: Beat egg whites and cream of tartar on high until frothy, about 30 seconds. Gradually beat in sugar. Continue on high until the sugar is dissolved (slide some between your thumb & finger- if you feel granules, it is not yet dissolved) and stiff peaks form, 4+ minutes.
Spoon the meringue over the pie, swirling and maximizing the peaks. Using a broiler or kitchen torch, brown the meringues. If broiling, move the oven rack so the pie is 6 inches from the element. Watch carefully as it only takes 2-3 minutes. Allow to cool slowly.