Panang curry is one of my favorite types of Thai curries. It is deeply flavored with spicy chili paste, hints of lime, and a nutty richness from the peanut butter. It is best to find a good quality panang curry paste for this recipe. Look for one at your local food co-op or health food store.
Panang curry paste is typically made from Thai red chilies, shallots, lemongrass, garlic, coriander, galangal (Thai ginger), kaffir lime peel, cumin, and sea salt. Some brands may contain shrimp paste so read labels. This is one of my favorite brands of organic Thai curry pastes.
The key to making really good curries is to first sauté the curry paste in oil. This brings out all of the flavors. I usually sauté the onion first (if using in a recipe), and then add the curry paste. Then add the liquids. This creates a solid foundation with an incredible depth of flavor. Another trick is to be very careful not to overcook the vegetables! Timing will depend on the sizes of your cut veggies, so watch them carefully. You'll want them in the crisp-tender stage when you turn off the heat as they will continue to cook in the hot liquid after the curry is done cooking.
If you would like more protein, feel free to add some cubed tofu, cooked chickpeas, or cubed halibut to the curry. If adding fish, add it when you add the broccoli and zucchini as it only takes a few minutes to cook. If you are on a vegan or vegetarian diet, replace the fish sauce with either coconut aminos or wheat-free tamari.