Preheat the oven to 350° F. Line a standard cupcake pan with cupcake liners.
Sift together the flour and salt in a bowl and set aside.
Place the butter in the bowl of a stand mixer (or use a hand-held electric mixer). Beat on medium speed until fluffy. Add the sugar and beat on medium speed until well incorporated.
Add the eggs and beat on low. Add the red food coloring, vanilla extract, and cocoa powder to the bowl. Mix on low until blended.
Add half of the flour mixture to the bowl and slowly pour in half the milk, beating until well incorporated. Scrape the sides of the bowl, then add the rest of the flour and milk. Beat just until fully combined.
In a small bowl, mix together the apple cider vinegar and baking soda until dissolved. Add to the batter and mix in on low speed, until fully incorporated.
Fill each well of the cupcake pan with the batter to two-thirds full. Bake for 12 to 15 minutes (start checking at 10 minutes) or until a toothpick inserted into the center of a cupcake comes out clean. Transfer the pan to a wire rack and cool completely.
Mix together the frosting ingredients and whip until smooth and stiff. Transfer frosting to a piping bag with a star tip and pipe onto the cupcakes.