Preheat oven to 350 degrees F and line 24 muffin tins with paper liners. In a mixing bowl, combine flour, corn starch, cocoa powder, baking powder, baking soda, and salt.
In the bowl of a standing electric mixer, beat butter and sugar until light and creamy. Add in the eggs one at a time, beating to incorporate each. Mix in the sour cream, vanilla, and food coloring. Mix in the flour until just combined, scraping the sides of the bowl as needed.
Spoon batter into cupcake liners and bake for 15-18 minutes or until toothpick comes out with only a few crumbs or clean. Cool completely before adding frosting.
For the Frosting:
Cream the butter and cream cheese together until smooth. Mix in the sugar and then the cream and vanilla. Place frosting in a piping bag fitted with a star tip (1M) and pipe onto cupcakes. Add sprinkles and top with a chocolate coin.
St. Patrick's Day Cupcakes https://www.garnishandglaze.com/green-velvet-st-patricks-day-cupcakes-recipe/