Preheat oven to 350ºF. P
lace cupcake liners into two 12-cup cupcake pans or two 9-cup mini cake pans.
In a large bowl cream butter, vanilla and sugar together.
Add eggs, one at a time, beating thoroughly after each addition until light and fluffy.
In a smaller bowl stir together the cocoa, flour, soda and salt.
Add this into the creamed mixture alternately with buttermilk, blending well.
Fill each cupcake liner 2/3 full.
Put pans into the oven and bake for 18 to 20 minutes, or until a toothpick inserted into the center of a cake comes out clean.
Remove pans from oven and set them on a rack.
Let cupcakes stand 5 minutes, then remove them from the pans to a rack.
When cooled, frost with the brown butter frosting.
For the brown butter frosting:
Melt butter in a medium sized heavy saucepan over low heat until deep golden brown.
Remove from heat and stir in confectioners’ sugar, half-and-half, corn syrup and vanilla extract. Beat well. Frosting should be creamy and soft yet stiff enough to to spread on cake.