Substitutions: You can replace the chicken with beef, shrimp, seafood, tofu, mushrooms, or various vegetables. For tofu, mushrooms, and quicker-cooking vegetables, extended simmering isn’t needed—except for dense root vegetables like carrots and potatoes. Sauté mushrooms and softer vegetables (such as squash, zucchini, or eggplant) and simmer them for about 5 minutes or until tender. If using tofu, simply heat it through since it’s already fully cooked; drain tofu for 15 minutes beforehand for better texture, then add it after incorporating the curry roux and warm for the final 5–10 minutes.