Place 3 1/2 cups chilly heavy cream within the bowl of a stand mixer fitted with the whisk attachment. (Alternatively, use a big bowl and electrical hand mixer.) Beat on medium pace till barely thickened, about 4 minutes. Add 1/2 cup powdered sugar, 2 teaspoons vanilla extract, and 1/4 teaspoon kosher salt, and proceed whipping till delicate peaks type,1 to 1 1/2 minutes extra. Add the remaining 1 1/2 cups chopped Oreo cookies, and blend on low pace till mixed and stiff peaks type.