01 - 
                Heat up your oven to 162°C. Prep a 9x13 pan with parchment and spray it generously with cooking spray. Place the flat side of two flower nails face-down in the pan, a few inches apart, and coat them with more spray.
              
              
              
                02 - 
                Use a large mixing bowl to stir together the flour, sugar, cocoa powder, baking powder, soda, and salt until they mix evenly.
              
              
              
                03 - 
                Dissolve espresso powder in hot water in a separate bowl. Add room-temperature buttermilk, sour cream, oil, eggs, and vanilla extract. Whisk until smooth.
              
              
              
                04 - 
                Gently mix half of the dry blend into the liquids until just combined. Add the remaining dry mixture and whisk lightly to avoid overmixing.
              
              
              
                05 - 
                Pour batter into your prepared pan, placing the flower nails evenly in the center. Tap the pan on the counter a couple of times to release air bubbles. Bake for 32-37 minutes, turning halfway for even heat.
              
              
              
                06 - 
                Let the cake cool in the pan for 15 minutes, then move to a rack to cool completely. Slice the fully cooled cake into 1-inch cubes using a serrated knife.
              
              
              
                07 - 
                While waiting for the cake, whisk pudding powder with chilled milk in a big bowl until completely smooth. Cover and pop it in the fridge to firm up.
              
              
              
                08 - 
                Blend the cold cream cheese on medium speed using a mixer until it’s lump-free. Add powdered sugar slowly while mixing to avoid mess. Beat for one minute on medium-high speed.
              
              
              
                09 - 
                Blend in vanilla extract with the cream cheese mix. Slowly add cold heavy cream along the bowl’s edge while the mixer runs on medium-high. Once thick, fold in the crushed Oreos by hand. Refrigerate until ready.
              
              
              
                10 - 
                Arrange half of the cut cake cubes in the base of a trifle dish. Spread half the chilled pudding evenly over the cake pieces.
              
              
              
                11 - 
                Sprinkle one cup of crushed or whole Oreo cookies on top of the pudding layer. Then, spread half of your Oreo whipped cream on top, smoothing it into a flat surface.
              
              
              
                12 - 
                Repeat cake, pudding, Oreo, and cream layers, finishing with whipped cream on top. Decorate with whole Oreos and small whipped cream swirls as a garnish.