Place the marrow bones on a baking sheet and sprinkle liberally with salt and pepper (on both sides, please!)
Roast bones in the oven for about 10-15 minutes, until they turn golden and marrow becomes soft and just barely starts to melt. You want to take them out of the oven when they get nicely crispy and golden and the marrow becomes soft and starts to bubble a little bit. Be careful not to overdo the cooking, or your marrow will end up completely melted down. The marrow, when done, should be enjoyably warm but not exactly hot.
Remove to a plate and serve with a side of fresh leafy greens, or continue with broth making
To make the broth
Add the roasted bones along with all the rest of the ingredients to a large saucepan or stockpot.
Bring to a roaring oil then lower heat, partly cover and simmer for 1 to 1½ hours, until the flavor of the broth is to your liking.
Strain through a fine mesh sieve and serve, or use in your favorite soups/recipes.