It's essentially bone broth served with the bone so that the marrow can be scooped out and relished.
This is an unintentional recipe. I was in the grocery to buy scrap bones to make bone broth when I discovered a huge pile of cross cut beef shank bones. I chose the six best looking ones and had them packed into two portions. Yesterday, I unwrapped the first portion, put them in the slow cooker, set the cooker on LOW and, for twelve hours, let the heat strip all the flavors from the bones. After cooling, I filled a half-gallon container with the strained broth then wondered what to do with the excess that still formed a pool at the bottom of the slow cooker. I thought for a few seconds and… the excess broth became this no-frills slow cooker beef bone marrow soup.
What does “no-frills” mean? Well, in the Philippines, beef bone marrow soup, or bulalo soup, is served with a bevy of vegetables and the shank used has a generous amount of meat attached to the bone. This no-frills slow cooker beef bone marrow soup is served with no vegetables except for a garnish of thinly sliced scallions. And the amount of meat clinging to the bone is negligible rather than generous. It’s essentially bone broth served with the bone so that the marrow can be scooped out and relished.
Will a spoon fit into the bone’s cavity? That depends on the size of the bone and the cavity. If the diameter of the cavity is narrower than the width of a soup spoon, provide a teaspoon (one with a long handle is ideal) for scooping out the marrow.
And if the cavity is narrower than the width of a teaspoon? Well, you have two options:
1. Provide a wooden spatula—the kind the accompanies ice scream—or a popsicle stick.
2. Something I’ve never tried but have seen in American TV shows—a large drinking straw. Instead of scooping out the marrow, it can be sipped.
And, here’s a tip for making the soup in the slow cooker.
If your beef shank bones are open on one side but closed on the other, and your slow cooker is large enough to hold all the bones in a single layer, position the bones in an upright fashion with the cut side up. By doing so, you can be sure that the marrow won’t fall off the bones and get mixed in the broth.
Place the beef shank bones in the slow cooker. If one side is closed and the other side open with the marrow exposed, place the bones closed side down to prevent the marrow from falling out.
Add the garlic cloves, onion halves, rosemary, salt and pepper to the bones.
Pour in one and a half to two liters of water (depending on the size of your slow cooker).
Set the slow cooker on LOW and leave for twelve hours.
Place the beef shank bones in soup bowls.
Taste the broth; add more salt and pepper, if needed. Strain.
Pour strained broth over the beef shank bones.
Sprinkle in finely sliced scallions before serving your no-frills slow cooker beef bone marrow soup. Remember to supple a teaspoon with a long handle, a wooden spatula or a popsicle stick for scooping out the bone marrow, or a large straw for sipping it instead.