Bulalo (Bone Marrow Soup) Recipe

Ingredients (14)

• 5 pounds (2.3kg) beef marrow bones, cut crosswise into 2-inch pieces (see note)
• 2 bone-in beef shanks (about 2 1/2 pounds)
• Kosher salt and freshly ground black pepper
• 2 ears sweet corn, shucked 
• 4 tablespoons (75ml) canola or other neutral oil, divided
• 2 medium garlic cloves, minced
• 1/2 medium red onion (4 ounces; 115g), cut into 1/8-inch-thick slices (reserve trimmings)
• 1/2 Napa cabbage (1 pound; 450g), cut into 3-inch-thick slices (reserve trimmings)
• 2 scallions, ends trimmed and sliced thinly on a bias, for garnish (reserve trimmings) 
• 1 pound (450g) beef tendons, rinsed and patted dry with paper towels (optional)
• 1 pound (450g) beef knuckles, rinsed and patted dry with paper towels (optional)
• Fish sauce, to taste
• 1 pound (450g) yellow fingerling potatoes (about 5 to 7 potatoes), scrubbed and cut into 2-inch pieces
• Cooked white rice, for serving