Lemon Meringue Tarts

Name: Lemon Meringue Tarts
Ingredients: 150 grams all-purpose flour, plus more for dusting; 1/2 teaspoon kosher salt; 110 grams (8 tablespoons) cold unsalted butter, sliced into very thin pats; 1/4 cup ice water; 4 large egg yolks (reserve whites for meringue); 50 grams (1/3 cup) cornstarch; 280 grams (1 1/3 cups) sugar; 1 1/2 cups water; 1/4 teaspoon kosher salt; 45 grams (3 tablespoons) unsalted butter; 1/2 cup lemon juice plus 1 tablespoon finely grated lemon zest; 4 large egg whites; 120 grams sugar; 1/2 teaspoon cream of tartar