Preheat the oven to 180°C (350°F) and line a 12-cup muffin tin with cupcake liners.

In a large bowl, lightly beat the egg with a whisk.

Add the oil, buttermilk, vinegar, vanilla extract, and red food coloring. Mix until smooth and well combined. Set aside.

In a separate bowl, whisk together the flour, sugar, cocoa powder, salt, and baking soda until evenly combined.

Pour the wet mixture into the dry ingredients.

Whisk vigorously for about one minute until the batter is completely smooth (do not overmix).

Divide the batter evenly into the cupcake liners, filling each about ⅔ full to prevent overflow.

Place in the oven and bake for approximately 18 minutes, or until a toothpick inserted in the center comes out clean.

Let the cupcakes cool completely on a wire rack before frosting.

Sift the powdered sugar

Beat the cream cheese and butter: In a large bowl, beat butter and cream cheese together on medium speed until creamy and fluffy.

Add the vanilla extract

Gradually add the powdered sugar: Add in three batches, beating well after each addition.

Scrape down the sides of the bowl to ensure even mixing.

Transfer the frosting to a piping bag fitted with a round tip (10-11 mm diameter).

Pipe the frosting in a spiral motion from the outer edge to the center, creating a delicate peak.

Sprinkle with red and pink sugar hearts or any decorations of your choice.