• Preheat the oven to 350F/180C. Line or grease a muffin pan.
• Mix butter and sugar until fluffy.
• Add eggs one by one, mix after adding each egg.
• Add vanilla.
• Add buttermilk and mix.
• Add flour and baking powder and mix until just combined and there are no lumps. Don’t over mix.
• Divide the batter between two bowls, add cocoa powder to one bowl and mix until just combined.
• Fill the muffin pan with cupcake batters alternatively, start with one tbsp. of vanilla and then 1 tbsp. of chocolate and continue until done. Or vice versa. Fill ⅔ of each muffin cup as they rise in the oven while baking.
• Bake in the oven for 25 minutes or until inserted toothpick comes out clean, without batter. Little bit of crumbs is ok.
• Make the chocolate glaze as the muffins are being baked.
• Let them cool completely and then glaze them with chocolate glaze.

Glaze:

• Put all the ingredients in a small pot and heat it on medium heat stirring occasionally until it starts boiling and thickens.
• Let cool for 10 minutes.
• Glaze the muffins.