In a large pot or deep sauté pan, add oil and heat on medium high. Then add the onions. Sauté until translucent and it starts to brown. Add the garlic and sauté for 30 seconds longer. If the bottom of the pan is starting to burn, add a little bit of water to deglaze. Then add the coriander, cumin, garam masala, turmeric, black pepper, red pepper flakes, and salt. Sauté for 30 seconds.
Add the cauliflower and potatoes and cook for 5 minutes, stirring often. You want the vegetables to start to soften. Add the tomatoes, half of the cilantro (1/4 cup), and the water. Stir everything and bring to a boil. Then lower heat to medium and cover the pot with a lid. Simmer for 10-15 minutes, stirring occasionally until vegetables are tender and cooked through.
Add the peas and the last half of the cilantro. Stir and cover for 2 minutes for the peas to cook. Then taste and add more salt and pepper if needed. Serve with rice (my favorite), naan, or as a side dish. Enjoy!