Preheat oven to 350 degrees. Prepare one cupcake pan by spraying with Pam and then lightly dusting with cocoa powder (tip: cocoa is a great alternative to flour when prepping a pan for chocolate cake or bread), set aside.
In a medium size mixing bowl, whisk or sift together flour, cocoa powder, sugar, baking soda, baking powder, and salt.
In the bowl of a stand mixer, add eggs, warm water w/ espresso powder, buttermilk, oil, and vanilla. Mix on medium speed until smooth. Turn down speed to low and slowly add the dry ingredients to the wet mixture. Mix until smooth (no flour/cocoa pockets remain), about 3 minutes.
Divide batter evenly among cups, filling ¾ of the way full. Place in oven and bake for 18-21 minutes, or until the tops spring back when touched and a cake tester comes out clean. Be careful not to over bake!
Remove from oven, allow them to sit for 3-4 minutes in the pan, and then transfer them to a wire rack.
Using a cupcake corer or a knife, remove the center of each hot cupcake. Place a truffle inside and then place top back on. Let cool while preparing the whipped topping.
In the (chilled) bowl of a stand mixer, on high, beat together heavy cream, confectioners sugar, cocoa powder and salt for approximately 2-3 minutes (or until mixture becomes stiff).
Turn cupcakes upside down (be careful, you’ll want to make sure that you plugged them up good to prevent leaks). Dust with cocoa powder, then top with chocolate whipped cream. Serve immediately!