Vietnamese lamb shanks with sweet potatoes

Name: Vietnamese lamb shanks with sweet potatoes
Prep time: PT30 minM
Yield: 2 servings
Ingredients: 2 tablespoons Ground Nut Oil; 4 Lamb Shanks; 2 Onion; 2 tbs chopped Ginger; 3 sliced thinly Garlic Clove; 1 chopped Red Chilli; 1 sliced Red Chilli; 1 tablespoon Brown Sugar; 1 tsp Brown Sugar; 3 Star Anise; 2 Lemongrass Stalks; 1L Lamb Stock; 1 ½ tbsp Tomato Puree; 4 Sweet Potatoes; 2 tablespoons Fish Sauce; Juice of 2 Lime; Handful Mint; Handful Basil Leaves