Escarole is a bitter green, I just love it. This is a good introduction if you never had it. The raisins sweeten it. The beans give it a nice richness. The vinegar cuts down the bitterness and the salty capers and anchovies makes for a dish with lots of flavor. The optional ingredients are for those that are not vegetarians. Do rinse the beans, anchovies and capers well to remove excess sodium.