1/8 tsp salt
Use a small paring knife to cut cones out of the tops of each cupcake. Fill with 2 teaspoons ganache. Spread 1 additional teaspoon ganache over top of cupcake to conceal hole. Set aside.
8 egg whites
2 c granulated sugar
1/2 tsp cream of tartar
2 tsp vanilla extract
Place egg whites, sugar and cream of tartar in work bowl of stand mixer. Set over pan of simmering water to make a double boiler. Whisk until sugar is dissolved and egg whites are frothy. Remove to stand mixer; add vanilla extract and whip on HIGH with whisk attachment for 5-7 minutes, or until fluffy stiff peaks form. Working quickly (before marshmallow sets), dollop 3 to 4 tablespoons (to your liking) atop each cupcake, spreading to edges and pulling up at the center to create a swirl.
With a kitchen torch, brown marshmallow topping. If desired, sprinkle cupcakes with any leftover crushed graham crackers. Makes 24 cupcakes.