Quick Chicken Curry with Spinach and Peas

Name: Quick Chicken Curry with Spinach and Peas
Ingredients: 2 pounds boneless, skinless chicken thighs, cut into 1 ½-inch pieces; Kosher salt and freshly ground pepper; 3 tablespoons unsalted butter; 3 shallots, halved and thinly sliced (1 cup); 1 cinnamon stick, broken in half; 2 tablespoons minced ginger (from a 2-inch piece); 1 ½ teaspoons ground coriander; ½ teaspoon ground turmeric; 1 red finger chile, thinly sliced (2 tablespoons); 2 teaspoons fresh lemon juice; 1 tablespoon sugar; 1 can (13.5 ounces) coconut milk; 1 cup frozen peas; 2 cups packed baby spinach; Steamed basmati rice, toasted sliced almonds, and cilantro leaves, for serving