Purple Sweet Potato Pie

Name: Purple Sweet Potato Pie
Prep time: 1 h
Cook time: 25 min
Total time: 1 h 25 min
Cuisine: American, Southern
Ingredients: 1 perfect pie crust; 1 pound Stokes purple sweet potatoes; 1 cup light brown sugar; 2 large eggs (room temperature ); 3/4 cup evaporated milk; 1/4 cup unsalted butter (melted); 1 tablespoon vanilla extract; 2 teaspoons pumpkin pie spice; 1/2 teaspoon kosher salt; 3 large egg whites (room temperature ); 1/4 teaspoon cream of tartar; 3/4 cup granulated sugar