How to Make It
Heat olive oil in a large skillet over medium-high. Sprinkle lamb shanks with salt and pepper. Cook until browned, about 3 minutes per side. Remove from skillet. Add onions, carrots, and garlic; cook, stirring occasionally, until slightly softened, about 4 minutes. Add red wine; cook, until mostly evaporated, about 3 minutes. Transfer to a 6-quart slow cooker. Stir in tomatoes, broth, and cumin. Nestle lamb into tomato mixture. Cover; cook on LOW until very tender, about 6 hours.
Transfer lamb to a plate. Pour cooking mixture through a wire-mesh strainer into a bowl; discard solids. Reserve strained liquid.