Head to your butcher or grocery store and ask for beef marrow bones. They’re usually dirt cheap, which is the universe’s way of saying “please make this.” You want a mix of knuckles, oxtail, and maybe a shank if you’re feeling fancy.
Now, do not skip this next bit: roast those bones. Pop them on a baking sheet and roast at 400°F (200°C) for 30 minutes until they’re browned and smell like heaven. It’s not mandatory, but roasting adds a deep, savory flavor that will make your broth deliriously happy.
Pro-tip: While the bones roast, wave them around the kitchen like a magic wand. I don’t know why—it just feels right.