Line muffin cups with cupcakes liners and preheat the oven to 350ºF/180ºC.
In a cup mix the oat milk with apple cider vinegar and let it curdle to form buttermilk.
In a large bowl whisk the buttermilk, oil and sugar until combined.
Stiff in the flour, cacao powder, baking powder and baking soda. Using a balloon whisk, whisk until everything is incorporated.
Add in the red food colouring and mix until combined. The amount of colouring you add will depend on the colour you want to achieve. I used 2 teaspoons.
Divide the batter between 10-12 cupcake liners about 2/3 full.
Bake for 18-20 minutes or until the toothpick comes out clean.
Remove from the oven and let it cool down in the pan for 5-10 minutes.
Then remove and let it cool completely on the wire rack.