In a bowl, mix all meatball ingredients until just combined. Form into small meatballs, about 1 inch in diameter. Wet your hands slightly if the mixture feels too sticky.

Heat a cast iron skillet over medium heat with a drizzle of oil. Sear the meatballs in batches until browned on all sides. Remove from the skillet and set aside.

Add the sliced bell pepper to the same skillet and cook for about 2 minutes, stirring occasionally. Mix in the zucchini and cook 2 more minutes, until tender. Transfer the vegetables to a plate.

In the same skillet, add a little more oil if needed. Sauté the minced garlic and grated ginger until fragrant, being careful not to burn them. Stir in the red curry paste and cook for a minute to deepen the flavors.

Pour in the coconut milk and chicken broth, stirring to combine. Add the fish sauce and brown sugar, then bring to a gentle simmer.

Return the meatballs to the skillet and let everything simmer until the meatballs are cooked through, about 10-12 minutes.

Stir in the pre-cooked bell peppers, zucchini, and baby spinach. Let the spinach wilt for about a minute, then squeeze in the lime juice and add the Thai basil.

Garnish with extra Thai basil if desired. Serve hot, ideally with jasmine rice or noodles.