Preheat oven to 350°F; grease and line two 9-inch cake pans.
Whisk flour, cocoa, sugar, baking powder, soda, and salt; add eggs, milk, oil, vanilla, then boiling water. Fold in crushed Oreos.
Divide batter into pans; bake 30–35 minutes. Cool completely.
Beat butter, powdered sugar, cream, vanilla, and salt for frosting; fold in crushed Oreos.
Taste and adjust the frosting with cream or salt.
Frost one layer, top with the second, and frost all over.
Garnish with Oreos or whipped cream; serve on a white ceramic stand.