Preheat oven to 425ºF. Place pie crust in a 9-inch pie plate; crimp edges. Line crust with parchment or foil and fill with raw rice. Bake pie crust for 15 minutes. Remove parchment and rice; discard. Bake crust 5 minutes longer, or until pale golden. Place crust on a wire rack to cool. Reduce oven temperature to 325ºF.
In a large saucepan, stir together 1 1/4 cups sugar, cornstarch, 1/4 tsp. salt, 1 1/2 cups water, lemon juice and zest, butter and egg yolks. Bring mixture to a simmer, whisking constantly, about 5 minutes. Simmer for 1 minute, until thick; do not boil. Scrape filling into pie crust.
In a large bowl, whisk egg whites with cream of tartar and 1/8 tsp. salt until soft peaks form. Whisk in remaining 2 Tbsp. sugar and beat until stiff, glossy peaks form, about 2 minutes.
Top pie filling with meringue, taking care to seal edges. Bake for 20 minutes, until nicely browned. Let cool on wire rack. Refrigerate for 2 hours, until set. Serve pie chilled or at room temperature.