If you grew up in the prairies, then your grandmother likely made flapper pie. It’s a treat that’s sweet, creamy and a little crunchy. We’ve given it a little update by turning the old fashioned delight into squares, but don’t worry – the recipe is still easy as pie.
Preheat oven to 350ºF. Line an 8×8-inch or 9×9-inch square baking dish with parchment, leaving overhang.
In a large bowl, mix to combine graham cracker crumbs, sugar, butter and cinnamon in a bowl. Firmly press graham mixture into prepared baking dish in an even layer. Bake for 10 minutes, until fragrant. Set aside to cool, about 1 hour.
In a large saucepan, whisk or stir to combine all custard ingredients.
Heat mixture over medium-high, stirring continuously while mixture comes to a boil. Once boiling, immediately reduce heat to low and continue to cook while whisking or stirring constantly until thickened and cornstarch is cooked, about 2 minutes. Set aside to cool slightly, about 30 minutes.
In a large bowl using a hand mixer or stand mixer, beat egg whites until foamy. Beat in cream of tartar. Gradually add in sugar while beating and continue to beat until stiff peaks form, about 5 minutes.
Arrange an oven rack for broiling. Set oven to broil.
Spread custard over graham crust, and then spoon meringue over custard. Dip the back of a spoon in meringue topping to create peaks and valleys. Broil until meringue has browned, about 1 minute (watch carefully to avoid burning).
Remove from oven and chill in refrigerator to set, about 30 minutes. Remove from pan to slice squares, or slice squares in the pan and serve. Store covered in refrigerator.