Preheat oven to 350º F. Prepare two 9-inch cake pans by spraying with baking spray or buttering and lightly flouring.
For the chocolate cake:
Add flour, sugar, cocoa, baking powder, baking soda, salt and espresso powder to a large bowl or the bowl of a stand mixer. Whisk through to combine or, using your paddle attachment, stir through flour mixture until combined well.
Add milk, vegetable oil, eggs, and vanilla to flour mixture and mix together on medium speed until well combined. Reduce speed and carefully add boiling water to the cake batter until well combined.
Distribute cake batter evenly between the two prepared cake pans. Bake for 30-35 minutes, until a toothpick or cake tester inserted in the center of the chocolate cake comes out clean.
Remove from the oven and allow to cool for about 10 minutes, remove from the pan and cool completely.
The cake batter will be very thin after adding the boiling water. This is correct and results in the most delicious and moist chocolate cake I've ever tasted! xoFreezer FriendlyLet the baked cake layers cool completely. Wrap them well with plastic wrap and then with foil. Put each layer into a freezer bag and freeze up to 2 months. To serve, thaw in the refrigerator overnight with wrapping intact. The next day, the layers are ready to fill and frost.High Altitude: If you live at a high altitude, adjust the recipe based upon the altitude for your area. Nutritional information is for the cake only.