Prepare and bake cake as directed on box. Allow to cool completely.
While cupcakes are cooling, add espresso powder to vanilla and let it dissolve. Mix the mousse ingredients together with a hand mixer until ingredients are incorporated and filling is creamy. Spoon mousse into a ziploc bag and seal. Refrigerate until ready to fill cupcakes.
When cupcakes are cool, take a paring knife and cut a circle in the top of the cupcake and gently lift and remove circle. Cut a bottom corner of the ziploc bag filled with mousse and squeeze mousse into the hole you made in the cupcakes. Place circle back on top of the filling. Don't worry that it stick up, you will never see it under the frosting. Do this to all the cupcakes. I had some pudding left over.
Dissolve espresso powder in vanilla. Combine frosting ingredients in a large bowl. Begin mixing on low speed until combined. Whip the frosting on high until fluffy and holds it's shape when peaks are formed. Be sure to taste the frosting, adding more espresso powder/vanilla as needed.
Frost cupcakes and top with chocolate sprinkles and espresso bean.