Preaheat the oven to 350°F and line a muffin pan with paper liners.
Heat milk in a saucepan over medium heat. When the milk begins to simmer, whisk in the cocoa powder and espresso powder until well combined. Set aside and allow to cool.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a separate bowl, beat together the sugar and oil until well combined. Add the eggs and peppermint extract and beat to combine.
Pour in the cocoa mixture and beat until smooth and mixed.
Spoon the batter into the prepared muffin pan and bake for 15 to 17 minutes, until a toothpick inserted into the center of the cupcake comes out clean.
Allow the cupcakes to cool completely before icing them.
To make the whipped cream frosting, add whipping cream to a chilled bowl and beat on medium speed until peaks begin to form.
Whisk together the powdered sugar and cocoa powder. Add the mixture to the cream along with the peppermint extract. Beat until the icing thickens and stiff peaks form.
Pipe the frosting on top of each cupcake before serving
Store in the refrigerator until ready to serve.
Notes
Before filling the cupcakes with batter, spray the paper liners with non-stick cooking spray so the cupcakes do not stick when removing after they're baked.