Wash and clean the cabbage, then dry thoroughly. Remove the outer leaves, chop into small sections, and set aside.
Add avocado oil to a large pan or wok and heat on medium-heat. When hot, add cumin seeds and mustard seeds (optional) and sauté until they splatter.
Add chopped onions and sauté for 3 minutes. Add minced garlic and ginger and fry for 30 seconds until fragrant. Take care not to burn the garlic.
Add tomatoes, peas, turmeric, garam masala, and red chili powder, and sauté until the tomatoes soften (about 3 minutes).
Add the chopped cabbage and salt and toss so the spices coat the cabbage evenly, and then fry until it's soft (about 5 minutes). Check to make sure the cabbage is soft but not mushy, and not hard or crunchy!
If you want a more creamy curry, add coconut milk at this stage, and stir to combine well.
Take off the heat, garnish with cilantro and serve hot, ideally with rice!
Notes
Clean the cabbage: To clean cabbage, you can remove the outer leaves and place it in a bowl of hot (but not boiling water) for 1-2 minutes. Just washing also works.
Make it oil-free. I use avocado oil in this recipe, but you can skip this by using water or vegetable broth to sauté the onions at the beginning.
Use pre-cut slaw. I like chunky pieces of cabbage in this curry, but you can speed things up by using pre-cut slaw mix. Just make sure it's not seasoned beforehand.
Don't overcook cabbage: Cabbage tends to sweat when cooked, so make sure that you're checking for the water released by cabbage. You can turn up the heat if you want a more dry curry, or add coconut milk for a creamy, indulgent curry.
Customize to your liking. Add a splash of hot sauce at the end for a spicier curry, or a touch of honey or maple syrup for a bit of sweetness. Switch up the herbs if you wish (or dislike cilantro).