Dice the chicken breast and cube the tofu. Slice the bell pepper and carrots, and cut the broccoli into florets.

Measure out the curry paste, coconut milk, fish sauce, brown sugar, and vegetable broth.

In a large skillet over medium heat, add the diced chicken and cook until browned, about 5-7 minutes.

If using tofu, add it after the chicken is cooked and sauté for an additional 2-3 minutes.

Add the sliced bell pepper, broccoli, and carrots to the skillet. Stir and cook for 3-4 minutes until slightly softened.

Stir in the Thai red curry paste and cook for 1 minute until fragrant.

Pour in the coconut milk and vegetable broth, then add the fish sauce and brown sugar. Stir to combine.

Bring the mixture to a gentle simmer and cook for 10 minutes, stirring occasionally.

Remove from heat and stir in lime juice and fresh basil before serving.