Preheat the oven at 175ºC conventional oven and prepare a 3 x 20 cm baking pan with parchment paper.
Separate the filling from the cookies of 8 Oreo cookies.
8 Oreos
Add the Oreo cookies into a freezer bag and crush them into smaller pieces. Mix together all the dry ingredients, with the crushed Oreo cookies and set it aside. Mix together the buttermilk and vanilla extract and set it aside.
320 g all-purpose flour, 2 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt, 280 g buttermilk, 1 teaspoon vanilla extract
In a mixing bowl, use the paddle attachment, add the Oreo filling, butter, vegetable oil, and sugar and mix it on high speed for 2 min.
160 g butter, 60 g vegetable oil, 310 g granulated sugar
Add the eggs one at a time into the mixture and mix it in until just combined.
3 eggs
Continue by alternating between adding the flour mixture and milk mixture, ending on the flour mixture.
Divide the cake batter into 3 prepared 20 cm baking tins and bake them for 20-22 min or until a cake tester comes out clean.
Let the cakes cool on a cooling rack. After 5 min, gently remove the cake from the cake tin and let the cakes cool down completely.