Preheat oven to 350°F (180°C). Line a 12-cup muffin tin with paper liners. In a large bowl, sift together flour, cocoa, baking soda and salt. Set aside.
Using an electric mixer (stand or hand-held) on medium speed, whisk canola oil and sugar for 2 min. Add egg and whisk until mixture is pale yellow and thickened, about 3 min.
In a small bowl, stir together buttermilk, 1 tsp (5 mL) vanilla, food colouring and vinegar. Reduce mixer speed to low, alternately add in buttermilk and flour mixtures and mix until just blended. Divide evenly into muffin tin and bake on middle rack of oven until a toothpick comes out clean, about 20 min. Transfer cupcakes to a rack to cool completely before icing.
To make icing, with mixer on medium, beat together cream cheese, butter and remaining vanilla until creamy, about 4 min. Reduce speed to low, slowly add icing sugar and mix until well blended. Ice cupcakes and store in an airtight container, at room temperature, for up to 3 days.
Top them with our Halloween Gravestone Cookies and chocolate wafer crumbs for an eerie graveyard garnish.