Pre-heat oven to 350 degrees.
Whisk together the flour, sugar, cocoa, baking soda, and salt in a large bowl.
In the bowl of a stand mixer or in a large bowl with a hand mixer, combine the buttermilk, oil, eggs, apple cider vinegar, vanilla, and food coloring.
Mix the dry ingredients into the wet ingredients gently until just combined, taking care not to over-mix.
Put papers into a cupcake tin and fill papers ¾ of the way full. Bake for about 20-22 minutes, until cupcakes are cooked through and springy to the touch. Let cool in the pan for a few minutes before moving to a wire rack to cool completely.
Once cooled, remove the center of each cupcake using a cupcake corer or knife. Fill middles of cupcakes with marshmallow fluff.
Drizzle chocolate ganache over the top and then place a Valentine's Day Peep on top.