Heat oven to 350.
Line cupcake tins with large or x-large paper cupcake cups.
In a bowl, whisk the cake flour, cocoa powder, cinnamon and salt.
In the bowl of a stand mixer or by hand, mix the oil and sugar well.
Add the eggs one at a time and mix until well combined.
Add the vanilla until combined.
Turn the mixer off and add the food colouring. Then, with the mixer on low, stir to combine.
Incorporate one third of the flour mixture until combined.
Incorporate half of the buttermilk or sour milk until combined.
Incorporate the second third of the flour mixture until combined.
Incorporate the second half of the buttermilk or sour milk until combined.
Incorporate the remaining flour mixture until combined.
In a small bowl, combine the vinegar and baking soda.
Quickly whisk into the flour mixture and combine quickly.
Fill cupcake liners 1/2 to 2/3 full and place tins in oven.
Bake 22-25 minutes.
Remove from oven and allow to cool in tins for 10-15 minutes.
Cool completely on wire racks.
Make the icing and chocolate decorations.
Ice liberally and top to your liking.