Prepare the rice: In a small pot over high heat, bring 2 cups of water to a boil. Add the brown rice, reduce the heat to low, and cover the pot. Simmer the rice, covered, for 45 minutes. Remove the rice from the heat and keep it covered for at least 10 minutes.
Sauté the aromatics: Heat a large nonstick sauté pan (skillet with sides) over medium-high heat. Add 2 tablespoons of the water and the garlic, lemongrass, ginger, and Thai pepper (optional). Sauté for about 1 minute, until fragrant.
Add the curry paste and vegetables: Add the curry paste, red bell pepper, carrots, broccoli, and spinach to the pan. Reduce heat to medium and sauté, stirring frequently, for approximately 10 to 12 minutes, or until the vegetables are fork-tender. Add a splash of the water at any point if the vegetables start to stick to the pan.
Add the remaining ingredients: Add the tofu, coconut milk, the rest of the water, tamari, and coconut sugar. Continue to sauté over medium heat, stirring occasionally, for about 5 minutes, or until warmed. Add the lime juice and remove from heat. Taste and add more lime juice, pepper, and/or water as needed to adjust the seasoning and spice level to your preference.
Serve: Serve the green curry over or next to the cooked brown rice. Garnish with fresh cilantro, fresh Thai basil leaves, chopped peanuts, and/or lime wedges.