You can eat this Paris-Brest ($4.75) from Maison Kayser like a candy bar. Most renditions of the hazelnut cream and choux paste treat are circular (and a touch unmanageable), but it's all too easy to down this one handed.
The hazelnut cream may not be the most intense in town (that honor remains Bosie Tea Parlor's, but it's heavy on the butter, giving it some M&M qualities: melts in your mouth, not in your hand.
Truth be told, the pastries at Maison Kayser can be hit and miss, as opposed to the always-excellent bread. But I'm a fan of this one—the choux paste remains crisp and eggy even after a lengthy stay in their chill case. A solid hazelnutty addition to the Upper East Side's pastry pantheon.