Preheat the oven to 350 degrees F.
In a large bowl, combine flour, baking soda, black cocoa, kosher salt, and espresso powder. Set aside.
Add room temperature butter and vegetable oil to a stand mixer with the paddle attachment. Cream together for 3 minutes, until smooth. Then add sugar and continue to mix for 2 minutes.
Add eggs one at a time, then add vanilla extract and vinegar and mix until combined.
Add half of the dry ingredients to the wet ingredients and mix together until combined. Then add half of the buttermilk. Repeat.
Spray 3 8-inch pans with nonstick baking spray. Divide the batter equally among the pans and bake for 30-33 minutes, until a tooth pick comes out clean. Allow the cakes to cool in the pan for 5 minutes, then turn the cakes out onto a wire rack or plate to cool completely.
While the cakes are cooling, make the Oreo Frosting. Add cold butter and cold cream cheese to the bowl of a stand mixer fitted with the paddle attachment. Cream together on low speed, increasing to medium speed until smooth.
Add powdered sugar one cup at a time, going from low speed to medium speed between each cup to ensure frosting is fluffy. After all of the powdered sugar is added, add heavy cream and vanilla extract and pinch of salt.
Fold in crushed oreo cookies.
Once the cakes are cooled, place one of the cakes on a cake stand. Level the cake if needed. Spread an even layer of oreo frosting all around the cake then place the second cake on top. Add an even layer of frosting and repeat with the third layer.
Place in the refrigerator for 30 minutes so that the icing can set. Then add another layer of frosting on top of the cake.
Optional: To pipe frosting on top, add leftover frosting to a piping bag with your favorite piping tip and pipe little domes on top of the cake. (I used Wilton piping tip 1A.)