- Preheat the oven to 325°F (165°C). Grease and flour a 10-inch Bundt or tube pan, making sure to coat every corner so the cake won’t stick. 
- In a large bowl, beat the softened butter and sugar together for about 4–5 minutes until light and fluffy. 
- Add the eggs one at a time, mixing well after each one. Stir in the vanilla extract. 
- In another bowl, whisk together the flour, baking powder, and salt. 
- Add the dry mix to the butter mixture in parts, alternating with the buttermilk. Begin and end with the flour. Mix just until everything is combined—don’t overmix. 
- Gently stir in the crushed Oreos with a spatula. Don’t mix too much—you want big Oreo pieces in every bite. 
- Pour the batter into your prepared pan and smooth the top. Bake for 70–80 minutes, or until a toothpick comes out clean. The top should be golden and a little cracked. 
- Let the cake sit in the pan for 15 minutes, then carefully flip it onto a wire rack to cool completely. 
- Whisk powdered sugar, cream (or milk), and vanilla in a small bowl until smooth. Drizzle over the cooled cake, and sprinkle extra crushed Oreos on top if you like.