Preheat your oven to 375°F (190°C) and prepare a jelly roll pan by lining it with parchment paper. This fundamental step ensures that your cake does not stick to the pan, making it easier to roll later.
In a large mixing bowl, whisk together 1 1/2 cups all-purpose flour, 1 cup granulated sugar, 2 tsp baking powder, and 1/2 tsp salt until well combined. This dry mixture sets the foundation of your cake.
Add in 1/2 cup unsalted butter (softened), 2 large eggs, 2 tsp vanilla extract, and 1 cup whole milk to the dry ingredients. Mix until smooth; this will create a lump-free batter.
Carefully pour the batter into the prepared jelly roll pan and use a spatula to spread it evenly. Bake for 12-15 minutes or until a toothpick inserted into the center comes out clean. You want the top to be golden brown.
Once baked, cool the cake in the pan for about 5 minutes. After cooling, gently roll the cake into a log shape with the parchment paper and allow it to cool completely. This step is crucial to avoid cracking when you unroll the cake later.
While the cake cools, prepare the filling. In a separate mixing bowl, beat together 8 oz softened cream cheese, 1/2 cup unsalted butter (softened), and 1 tsp vanilla extract until smooth and creamy.
Gradually add 2 cups powdered sugar to the mixture, continuing to mix until fully incorporated. This creates a sweet and silky filling. Finally, fold in 1 cup crushed Oreo cookies with a spatula.
After the cake has cooled, gently unroll it and spread the cream cheese filling evenly over the surface. Be careful to spread it to the edges, allowing for a generous filling in each bite.
Once filled, carefully reroll the cake tightly without the parchment paper and wrap it in plastic wrap. Chill in the refrigerator for at least 30 minutes before serving; this helps set the filling and makes slicing easier.