Sweet Potato Curry with Mussels

Name: Sweet Potato Curry with Mussels
Ingredients: 3 tablespoons grapeseed oil; 1 cup thinly sliced onions; 2 cloves garlic, minced; 10 curry leaves; 1 tablespoon garam masala; 1 teaspoon black mustard seeds; 1 teaspoon smoked paprika; 1 teaspoon turmeric; 2 cups chopped fresh tomatoes; 2 tablespoons tomato paste; A pinch of salt; A pinch of pepper; 2 cups chopped sweet potatoes; 2 cups vegetable broth; 1 cup yogurt; 2 pounds mussels, cleaned and debearded; Steamed rice, roti or toasted bread, for serving