Preheat oven to 325F and line a cupcake tin with liners.
If you are using the instant coffee: in a small bowl, mix together the instant coffee granules and water until the granules are dissolved. Set aside.
In a medium-sized bowl, whisk together the flour, dark cocoa powder, baking powder, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or a medium-sized bowl if using a handheld mixer, beat the butter and oil together until combined and completely homogeneous - this will only happen if the butter is completely at room temperature. About 2-3 minutes on high speed.
With the mixer on low, stream in the granulated sugar, then turn it up to medium-high speed and beat until light and fluffy. About 1 minute, scraping down the sides and bottom of the bowl as necessary.
Then, with the mixer on low, add the eggs in, one at a time, scraping down the sides and mixing well in between each addition. Add the vanilla extract and coffee mixture (if using) and mix on low until combined.
Add half of the dry ingredients and mix on low until just combined. Add half of the milk and half of the yogurt and mix on low until just combined. Stop and scrape down the bottoms and sides of the bowl. Repeat this with the remaining halves of dry ingredients, milk and yogurt. Do not over mix!
Fill the cupcake liners with batter so they are about ½ full. Bake the cupcakes for 18-21 minutes until a toothpick inserted into the center comes out clean. Let cool in the pan for 5 minutes, then remove the cupcakes from the pan to cool completely.