Boston cream pie

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A round cake with a custard or cream filling, often topped with a chocolate glaze.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A round cake that is split, filled with custard or cream, and frosted with chocolate, the official dessert of the Commonwealth of Massachusetts.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun layer cake filled with custard