Paella Valenciana

Name: Paella Valenciana
Ingredients: 3 tablespoons extra-virgin olive oil; 1 large onion, thinly sliced; 1 garlic clove, thinly sliced; 3 whole chicken legs, split into thighs and drumsticks; Salt and freshly ground black pepper; 3 ounces Spanish chorizo, finely diced; 1 cup sliced piquillo peppers (from a 9-ounce jar); One 15-ounce can large butter beans, drained and rinsed; 5 cups chicken stock or low-sodium broth; Pinch of saffron threads, crumbled; 2 cups arborio rice (15 ounces); 1/2 cup frozen baby peas; 24 mussels, scrubbed and debearded (about 1 pound); 24 littleneck clams, scrubbed; 6 jumbo shrimp in their shells, butterflied and deveined