In a Dutch oven or large heavy bottom pan, heat the oil over medium-low heat.
Add the garlic, ginger, onions (or shallots) and lemongrass and sauté stirring frequently for about 2-3 minutes or until the onions start to soften and the rest of the ingredients become aromatic. Make sure the garlic doesn’t burn.
Stir in the red curry paste and sauté for about 2 minutes then, stir in the coconut milk, Kaffir lime leaves (optional), chicken broth, fish sauce, soy sauce and brown sugar. Mix to combine.
Bring the mixture to a quick boil, lower the heat and simmer for about 10 minutes or until the sauce thickens a bit.
Add the carrots and chicken and cook for about 5 - 6 minutes or until the chicken is just cooked through. Add the red bell pepper and zucchini and cook for about 4 minutes or until the vegetables soften. Add the broccoli florets, basil and cilantro. Mix well, cover the pot and simmer for about 2 minutes. The broccoli cooks pretty fast so keep an eye on it.
Before serving, remove the lemongrass. To serve, garnish with additional basil and cilantro and lime wedges if desired.