Heat oven to 350 Line 24 muffin cups with paper liners.
Combine the flour, cocoa, baking soda, and salt in a medium bowl. Whisk to blend .Combine the buttermilk and vanilla in a measuring cup.
Beat the butter and sugar in a medium bowl with a
electric mixer on medium high speed until light and fluffy. Add the eggs one at a time beating after each addition . Add the flour mixture alternating with the buttermilk mixture starting and ending with the flour mixture.
Divide the batter between the prepared muffin pans .Bake until a toothpick inserted in the center comes out clean 18 to 20 minutes.
Transfer to a wire rack and cool 10 minutes .Invert and cool completely.
Filling and swirl:
Beat butter in a medium size bowl until light and fluffy. Gradually add powered sugar .Add 2 tablespoons of the milk and beat 5 minutes until almost white and light and fluffy. Add additional milk if mixture is too thick. Spoon frosting into
a pastry bag fitted with a medium -size plain round tip. Remove cakes from pan .Insert tip of pastry bag into top of cakes, about 1/2 inch deep and squeeze.
Meanwhile ,make the Glaze ,Heat the cream and corn syrup in a small saucepan over medium heat until it just comes to a boil.
Remove from heat and stir in the chocolate chips
cover and let stand 5 minutes .Whisk till smooth .
Dip the tops of the filled cupcakes into the chocolate glaze .Place on a cooling rack to set for 10 minutes.
Change the piping tip for the vanilla frosting to a smaller round tip .Pipe decorative swirls on top of each glazed cup cake
prep time 20 minutes
bake time 20 minutes