Bone marrow is the adipose tissue that resides inside an animal’s hollow bones. It is of two types: red bone marrow generates new blood cells, while yellow bone marrow is mainly fat. As an animal ages, much of what what was originally red bone marrow turns into yellow bone marrow.
For culinary purposes, most bone marrow is the tissue inside the shin bone of a cow, pig, or lamb. It is much prized by the French and the Fujianese, and ignored by most of the world’s other culinary traditions. The French manufacture narrow spoons to scoop the roasted marrow from bones, while the Fujianese deposit the bones directly into soups.
The marrow, mostly fat, is delicious, and commonly spread on toast and served with sea salt. I recently encountered it at Roberta’s, the hipster pizza hang hidden in a Bushwick industrial neighborhood. Depending on who you believe, it may or may not be the city’s foremost purveyor of Naples-style one-person pizzas.
At Roberta’s, a pork shin is split up the middle and roasted in the wood-burning oven, which renders the fatty tissue smoky and gelatinous. Just the thing to spread on a piece of toast, with a sprinkle of coarse salt and, if you want, a little sprig of parsley, which is grown on the roof of the pizzeria. 261 Moore Street, Brooklyn, 718-417-1118
Below: Various types of bone-marrow extraction devices