
1 1/2 cups all-purpose flour
1/3 cup plus 3 tablespoons sugar
Kosher salt
1 stick unsalted butter, cut into small pieces
1/2 teaspoon finely grated lemon zest
1 whole egg plus 2 egg whites
1 litre lemon ice cream, softened
8 to 10 drops yellow food coloring, optional
1/2 teaspoon pure vanilla extract