Chicken Tikka Masala

Name: Chicken Tikka Masala
Ingredients: 1/2 cup (4 oz./125 g) plain whole-milk yogurt; 4 tsp. peeled and grated fresh ginger; 4 garlic cloves, minced; 2 tsp. garam masala; Kosher salt and freshly ground pepper; 3 boneless, skinless chicken breasts, about 1 1/2 lb. (750 g) total; 2 Tbs. olive oil; 1/2 yellow onion, thinly sliced; 1/2 tsp. chili powder; 1/4 tsp. paprika; 1 can (14 1/2 oz./455 g) chopped tomatoes; 2 tsp. tomato paste; 1/2 cup (4 fl. oz./125 ml) heavy cream; 1/4 cup (1 1/2 oz./45 g) thawed frozen peas; Chopped fresh cilantro for garnish