A nutty crust, a creamy custard filling, and a towering crown of meringue? Yep. We’re on Team (Ice Cream) Pie.
Preheat the oven to 400°. In a food processor, pulse the nuts just until finely chopped. (Don’t overprocess or the nuts will turn into a paste.) In a 9-inch deep-dish pie plate, mix the nuts, 1/3 cup sugar, the butter, and salt. Press into the bottom and up the sides of the pie plate. Bake until deep golden-brown, 10 to 15 minutes. Let cool on a wire rack.
In a saucepan, bring the cream and 1 cup sugar to a boil, stirring until the sugar dissolves. Reduce heat to medium-low. Let simmer for 3 minutes. Remove from heat. Whisk in the citrus zests and juices, then the yogurt. Pour into the cooled piecrust. Refrigerate for 30 minutes. Cover and freeze until the filling is firm, about 6 hours.
Preheat the oven to 500°. In a large bowl, beat the egg whites and cream of tartar until soft peaks form. Gradually beat in the remaining 1/2 cup sugar. Continue to beat until stiff peaks form. Spread the meringue over the frozen pie. Bake until browned in spots, about 3 minutes.