Add the butter, cream cheese and shortening in a mixing bowl fitted with a paddle attachment. Beat on high until light and fluffy. It's very important all of the ingredients are room temperature so there are no clumps.
Scrape down sides of bowl and slowly stream in corn syrup and 1 tablespoon vanilla. Beat until mixture is silky smooth and glossy white, about 3 minutes.
Scrape down sides of bowl and, with mixer on low, add powdered sugar, salt, baking powder, and citric acid until just combined. Increase speed to medium-high and beat until you have a brilliant stark white, beautifully smooth frosting, about 4 minutes until super white and fluffy.
Stir in the crushed Oreos last with just a few strokes.
Store frosting in an airtight container in fridge up to 1 week.