Heat oven to 350°F. Grease 9x13 pan. Or 30 cupcakes or 2 (9-inch) round cake pans.
In a small saucepan over low heat melt chocolate, butter, and boiling water. Stir until melted and smooth. Set aside.
In a large bowl stir together flour, sugar, baking soda, and salt.
In a small mixing bowl, beat eggs with a whisk and then whisk in the sour cream and vanilla until smooth.
Slowly add the melted chocolate mixture to the dry ingredient mixture. Stir until combined.
Add the egg mixture and stir until silky smooth.
Pour into a 9x13-inch cake pan and bake at 350 degrees Fahrenheit for 35-40 minutes.
For 2 (9-inch) cakes bake for 35-40 minutes. For 2½ dozen regular cupcakes bake 25 minutes.
Fudge Frosting
Over low heat, melt the chocolate chips. Set aside to cool slightly.
In a separate bowl, beat shortening and butter with an electric mixer until smooth. Add vanilla.
One cup at a time, add the powdered sugar to the shortening mix.
Pour cooled chocolate into the frosting mixture. Add milk as needed to get to your desired spreading consistency. Frost the completely cooled cakes or cupcakes.