Heat oil in a large pan or wok over medium heat. Add chopped onions and sauté until softened.
Stir in curry paste and cook for 1-2 minutes until fragrant. You can adjust the amount based on spice preference.
Add coconut milk to the pan, stirring to mix with the curry paste. Let it simmer on low for 5 minutes.
Add chicken, tofu, or vegetables. Stir to coat in the sauce and cook until the protein or veggies are tender.
Throw in your choice of vegetables (bell peppers, carrots, spring onions, etc.). Let them cook in the curry sauce for 5-7 minutes.
Season with salt or a dash of fish sauce or soy sauce for extra flavor. Adjust heat level with chili if desired.
Garnish with fresh basil or coriander and serve with steamed rice. Enjoy your creamy, flavorful Thai curry!