This warm, gooey, flourless chocolate cake requires just three ingredients, five minutes and a zap in the microwave. Nutella does the heavy lifting here, standing in for sugar, fat and flour and offering its milky cocoa sweetness and toasty hazelnut flavor to every spoonful. This cake is best slightly underbaked so the center is molten like a lava cake. A dollop of vanilla ice cream or Greek yogurt is optional, but a wonderful way to balance the richness of the cake beneath.
