1. Preheat the oven to 350 degrees. Line 2 cupcake tins with paper liners and set aside. 

2. Crush the graham crackers to fine crumbs. The finer, the better. Mix with 1/4 cup sugar, and 5 tablespoons melted butter. 

3. Press 1 tablespoon of the crumb mixture into the bottom of the prepared paper liners. Be sure to press firmly. 

4. Bake 8 minutes. Set aside. 

1. Whisk together the flour, salt, baking soda, and cocoa powder in a medium bowl or measuring cup. Set aside. 

2. Combine the butter and 1 cup sugar into a mixing bowl, or the bowl of an electric mixer, and stir until light and fluffy. About 3 minutes. 

3. Stir in the melted chocolate. 

4. Add the eggs, one at a time, followed by the egg yolks. Stir until incorporated. 

5. Scrape the sides of the bowl Add the oil, vanilla, and sour cream. 

6. Scrape the side of the bowl again, and stir in the dry ingredients with the water until just incorporated. 

7. Divide the batter over the prepared graham cracker crust, filling 2/3 full. 

8. Bake 13 to 15 minutes, or until a toothpick comes out clean. Cool completely.

For the frosting: 

1. Add the soft butter with the marshmallow cream into a mixing bowl. Mix with a handheld or stand mixer until incorporated. 

2. Add the powdered sugar and vanilla extract. Stir until combined. 

3. Pipe or spread onto your cool cupcakes.