Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, and grease with cooking spay, set aside.

In a large bowl, whisk together the flour, sugar, baking powder, baking soda and salt until well combined. Make a well in the center and add in the buttermilk, oil, egg and vanilla. Stir until just combined. Slowly whisk in the hot water. The batter will be thin. Fold in the crushed cookies and then pour into the prepared pan. Bake until golden brown and a toothpick, inserted in the middle, comes out clean, about 25 to 30 minutes. Remove from the oven and let cool completely.

To make the frosting, beat the butter until light and fluffy. Add in the powdered sugar, vanilla and heavy cream and beat until thick and creamy. Pour onto the cooled cake and spread with an offset spatula. Top with the crushed cookies before slicing and serving. Leftovers can be wrapped in plastic and stored at room temperature for up to 3 days. Enjoy!