Preheat your oven to 350°F (175°C) and line a 12-cup muffin pan with cupcake liners.

In a large bowl, beat together the softened butter, sugar, and vegetable oil until light and fluffy, about 2-3 minutes.

Add the egg and vanilla extract, beating until fully incorporated.

In a separate bowl, sift together the flour, cocoa powder, and salt.

Add half of the dry ingredients to the wet ingredients, mixing on low speed until just combined.

Pour in the buttermilk, followed by the remaining dry ingredients, mixing gently to avoid over-mixing.

In a small bowl, combine the baking soda and vinegar (it will bubble up). Quickly add this mixture to the batter and mix well.

Add pink food coloring, a few drops at a time, until you reach your desired shade of pink. Stir gently to ensure the color is evenly distributed.

Fill each cupcake liner about 2/3 full with batter.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean.

Remove the cupcakes from the oven and let them cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

In a large mixing bowl, beat the softened butter on high speed until creamy and smooth, about 2 minutes.

Gradually add the powdered sugar, one cup at a time, beating on low speed until combined.

Add the vanilla extract and a pinch of salt, then beat on medium-high speed until fully incorporated.

Slowly add the heavy cream, one tablespoon at a time, until the frosting reaches a smooth, spreadable consistency.

Continue beating on high speed for 2-3 minutes to make the frosting extra fluffy.

Using a piping bag fitted with a large star tip, pipe a generous swirl of frosting onto each cooled cupcake.

For a touch of sparkle, sprinkle each cupcake with pink sanding sugar or edible glitter.