For Cupcakes: Combine flour, cocoa, baking soda and salt in a medium bowl, whisk to blend.
Combine buttermilk and vanilla as well.
Beat butter and sugar with an electric mixer on medium-high speed until light and fluffy.
Add eggs, one at a time, beating well after each addition.
Add the flour mixture alternating with the buttermilk mixture, starting and ending with the flour mixture.
Divide batter among prepared muffin pans and bake until toothpick inserted comes out clean, about 18-20 minutes.
Let cool for 10 minutes and then take cupcakes out of pans to cool completely.
For Filling and Swirl: Beat butter with an electric mixer until light and fluffy.
Gradually add powdered sugar.
Add 2 Tbsp of milk and beat for 5 minutes, until almost white and light and fluffy.
Add additional milk if mixture is too thick.
Spoon frosting into a pastry bag with a medium-sized round tip.
Place tip into center tops of cupcakes about ½ inch deep and squeeze to fill!
For Glaze: Heat corn syrup and cream in a small saucepan over medium heat until it just comes to a boil.
Remove from heat and stir in chocolate chips.
Cover and let stand 5 minutes. Whisk until smooth.
Dip tops of filled cupcakes into the chocolate glaze and place on a cooling rack to set for 10 minutes. Then, using a smaller round tip in your pastry bag, pipe decorative swirls on top of your glazed cupcakes.
Recipe by Smashed Peas & Carrots at https://smashedpeasandcarrots.com/squiggles-of-deliciousness/