• Preheat the oven to 350°F (180°C). Line a cupcake pan with 6 liners. Set aside.

For the cupcakes:

• In a large bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.
• In a medium bowl, whisk together the egg, granulated sugar, brown sugar, oil, and vanilla.
• Pour half of the wet ingredients into the dry ingredients, along with half the buttermilk. Whisk for a few seconds. Repeat with the remaining wet ingredients and buttermilk. Stir just until combined; avoid overmixing.
• Spoon the batter into the cupcake liners to 1/2 full.
• Bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean.
• Remove from oven and allow to cool completely in the pan.

For the frosting:

• With a handheld mixer or stand mixer fitted with a whisk attachment, beat butter on high speed for about 3 minutes or until creamy and lightened in color, scraping down the bowl as needed.
• Add powdered sugar, vanilla extract, and milk.
• Beat on low speed until sugar is incorporated. Increase speed and beat for 3 minutes, scraping the bowl several times.
• Add the red food coloring and stir until well mixed. Add more as needed to reach a rich color.

To assemble to cupcakes:

• To assemble the cupcakes, spoon the red frosting into a piping bag with a large round tip.
• Pipe a large dollop onto each cupcake.
• Press two candy eyes into the front of the frosting. Use the black frosting pen to add little black hearts.