Four years ago, the founder of this site wrote about an amusing experience with cheesecake geometry he had while visiting Lady M's original Upper East Side cake boutique. Much has changed since then. First, Lady M has become much more accessible. Back in 2009, if you wanted one of their cakes, your only options were to visit their Upper East Side shop or one of the restaurants to which it wholesaled. Now there are three shops in New York, including one in the heart of midtown right off Bryant Park.
They've also—thankfully—relaxed a bit. When I recently visited their second new outpost at the Plaza Food Hall, people were snapping photos of their cakes left and right and nobody behind the counter raised an eyebrow. (This used to be forbidden at their Upper East Side shop.) The popular attention has solidified their mille crepe cake as one of the city's "must-try" desserts, a form often imitated elsewhere.
Every fall, Lady M sells an excellent, seasonal cake referred to as a Pumpkin Nuage ($7.50). Though pricy, it delivers an eating experience worthy of its name: "cloud cake." The low-sweetness cake is a combination of a very good pumpkin pie and a cheesecake, but lighter than either—more akin to mousse. You can detect some pumpkin pie spices like cinnamon, but the cake lacks the unpleasant graininess of some pies, and the graham cracker crust is lighter than most.
It would be hard to visit Lady M without ordering one of their crepe cakes (now in 8 different varieties; I like the banana chocolate), so I recommend visiting with a friend and splitting two cakes if you plan to order the nuage.