Start by gathering all your ingredients. Chop the NY Strip Steak into thin strips, and prepare your vegetables by chopping the onion, carrots, zucchini, and red bell pepper. Mince the garlic and grate the ginger to have everything ready for cooking.
In a large skillet or wok, heat the avocado oil over medium-high heat. Once the oil is hot, add the chopped onion and sauté for about 2-3 minutes until it becomes translucent.
Add the NY Strip Steak to the skillet, cooking it for about 4-5 minutes until it is browned on all sides. Make sure to stir occasionally to ensure even cooking.
Next, toss in the minced garlic, grated ginger, carrots, zucchini, and red bell pepper. Sauté for an additional 5 minutes until the vegetables begin to soften.
Pour in the two cans of full-fat coconut milk and stir well to combine all the ingredients. Add the red curry paste and fish sauce (if using), mixing thoroughly to ensure the curry paste is well incorporated into the sauce.
Add sea salt to taste. Bring the mixture to a gentle simmer and let it cook for about 10-15 minutes, allowing the flavors to meld and the sauce to thicken.
Once the curry is done, remove it from heat. Serve it hot, garnished with fresh Thai basil leaves for an aromatic finish. Pair it with steamed rice or noodles for a complete meal.