Prepare the caramel and set aside to cool and thicken.
Whisk together the flour, cocoa powder, baking powder and salt. Set aside.
Beat together the butter and oil until combined. Add the granulated sugar and beat until light and fluffy. Add the eggs and beat until combined.
Beat in the vanilla & coffee mixture. Add half of the dry ingredients & mix. Add half of the milk & yogurt & mix. Repeat with the other halves of dry ingredients, milk & yogurt.
Fill the cupcake tin and bake for 18-20 minutes at 325 degrees Fahrenheit.
Beat the butter until fluffy. Beat in the cocoa powder, powdered sugar and salt. Add the milk and beat until combined.
Poke the bottom of a piping tip into the cupcake & twist. Fill the hole you created with caramel. Seal the hole with the piece of cupcake you removed. Or use a sharp knife to make the hole and follow the same instructions above.
Once the cupcakes are filled, frost with the buttercream and drizzle even more caramel on top. Enjoy!