• Grease a cupcake tin or line with cupcake papers. Heat oven to 350 F.
• In a mixing bowl, combine the flour, granulated sugar, baking soda, 3/4 teaspoon of salt, cocoa, canola oil, coffee, 2 teaspoons of vanilla, and the vinegar. Beat with an electric mixer on medium speed until smooth and well blended.
• Fill the prepared cupcake cups about half full.
• Bake the cupcakes for 25 to 30 minutes, or until a cake tester or wooden pick comes out clean when inserted into the center of a cupcake.
• Cool on a rack and frost as desired.

For the Buttercream Frosting

• In a mixing bowl with an electric mixer, beat the 4 ounces of butter until smooth and creamy.
• Sift the powdered sugar. With the mixer on low speed, gradually add the powdered sugar to the butter.
• Beat in the salt and vanilla.
• Add the milk and beat on medium-high speed for 3 to 4 minutes. Adjust with more powdered sugar or more milk, if necessary for piping consistency.