PREPARATION
To prepare chili, heat olive oil over medium-low heat in a deep, wide pan with a lid. Add onions, garlic and bell peppers, and sauté until softened, about 5 minutes. Stir in red pepper flakes, coriander, cumin and cardamom pods. Stir in lentils.
Add chopped tomatoes, kidney beans, ketchup, tomato paste, cocoa, kale (optional) and 3 cups water. Stir well. Cover, and simmer, stirring frequently, until mixture is thickened and beans are tender, about 45 minutes (or cook in slow cooker).
Chili can be made ahead to this point and topping added later. (In that case, cover, and refrigerate for up to 3 days, bringing to room temperature before proceeding.)