Crust:
•2 cups shortbread cookies
•1/4 cup (1/2 stick) unsalted butter, melted

Curd: (or use store-bought)
•2 1/4 cups sugar
•1 cup freshly squeezed lemon juice
•3/4 cup (1 1/2 sticks) unsalted butter, cubed
•4 large eggs
•3 large egg yolks
•1 tablespoon cornstarch

Mousse:
•1 1/2 cups heavy whipping cream, cold
•3/4 cup sugar
•5 large egg whites
•1/3-1/2 cup water
•4 teaspoon unflavored gelatin