A few blocks from where the Cronut was born, a new pastry mash-up by a French chef is making its debut. Gregory Doyen developed a cakelike confection inspired by brownies and cookies that’s round, about three inches in diameter, fairly dense and with a central opening where a ganache or fruit filling goes. Mr. Doyen is calling it MOD, for multilayered original dessert. It’s offered as a single serving ($7.50 each) and in fours ($29), and can be shared and personalized. In a show of extreme confidence, it’s the only product sold in the bright white shop of the same name he owns with Edward Geyman, his business partner. A native of the Burgundy region in France who studied pastry-making and has been a pastry consultant in many countries around the globe, Mr. Doyen, 38, arrived in the United States a year ago and began working on this project. “I didn’t just want to reproduce French pastry,” he said. The flavor and filling combinations are endless. For now he has eight colorful examples, including peanut butter and jelly, matcha with white chocolate, walnut with dark chocolate, red velvet with dark chocolate and raspberry, and pecan caramel with milk chocolate chips and sea salt. He has a featured flavor of the month, which for now is s’mores with a marshmallow topping that he torches before serving. He said he’s working on a mini size.