S'mores Cupcakes

Name: S'mores Cupcakes
Prep time: 30 min
Cook time: 20 min
Total time: 50 min
Cuisine: American
Ingredients: 4 ounces dark chocolate (chopped); 1/2 cup heavy cream; 1 1/4 cup cake flour (substitute all purpose flour); 1/2 cup graham cracker crumbs (about 5-7 graham crackers); 1 1/2 teaspoons baking powder; 1/4 teaspoon salt; 1/2 cup vegetable oil; 1/2 cup granulated sugar; 1/2 cup brown sugar; 2 large eggs (room temperature ); 1 teaspoon vanilla extract; 1/2 cup whole milk; 5 large egg whites (room temperature); 1 1/2 cups granulated sugar; 1/2 teaspoon cream of tartar