1. Make the crust: In a medium bowl, combine gingersnaps, butter, sugar, and our. Mix until it resembles wet sand. Press into a buttered 9-inch tart pan or pie plate, covering bottom and sides. Freeze
for 30 minutes to set. Preheat oven to 350 degrees. Bake for 12 minutes. Let cool completely before lling. (This can be made a day ahead.) Increase oven to 375 degrees.
2. Make the custard: Combine butter, lime zest and juice, ginger, and sugar in medium saucepan. Whisk over medium-low heat until butter is melted and ingredients are emulsi ed. In a large bowl, whisk eggs, yolks, and salt. Slowly add half of warm mixture into eggs, whisking to combine. Pour warmed eggs back into saucepan over medium-low heat, whisking constantly, and cook for 3 to 5 minutes until it reaches a pudding-like consistency.
3. Remove from heat and pour immediately into gingersnap shell. Bake for 10 minutes or until set.
4. Make the meringue: Heat an inch of water in a pot until simmering (one that your mixer bowl will rest on without touching water). In bowl of a stand mixer (or a large bowl with hand mixer), combine egg, sugar, and salt. Place mixture over simmering water and whisk until it reaches 120 degrees on a candy thermometer. Transfer to mixer and beat until doubled in volume and peaks are glossy, about 6 to 8 minutes.
5. Dollop meringue over custard and smooth out with a spatula, making swirls and peaks. Preheat broiler and place pie about 6 inches below. Toast meringue until golden, about 5 to 7 minutes. Serve immediately or keep refrigerated.