In a large pot, heat the oil over medium-high heat. Add the onion and stir, cooking until lightly golden, about 3-4 minutes. Reduce heat to medium, add the garlic and ginger, cooking stirring for one minute.
Add the coriander, cumin, turmeric, cayenne, brown sugar, garam masala, salt and pepper, stir and cook for 30 seconds.
Add the tomato paste and stir to combine, cook about 1 minute.
Add the stock, coconut milk and cinnamon and bring to a boil. Reduce the heat to low and simmer, uncovered, for 10 minutes.
Add the cauliflower, potatoes, tomatoes and peas. Bring to a boil again, then reduce the heat to low, cover and simmer until the veggies are tender, about 20 minutes.
Stir in the lime juice and zest, cook for about 3 minutes more.
Add the spinach and let wilt in the hot curry. Serve over rice and garnish with cilantro. Can also top with a dollop of non-dairy yogurt or Raita. Enjoy!