Turn your slow cooker to high heat to preheat it while you prepare the other ingredients. Dice the onion if using fresh, and mince the garlic and ginger. Drain and rinse the chickpeas. Cut the cauliflower into florets if not already done. If you're using dried versions of the onion or garlic, have them ready to add.

Add the prepared cauliflower, chickpeas, onion, garlic, and ginger to the preheated slow cooker. Pour in the two cans of chopped tomatoes and half a cup of shaken coconut milk. Sprinkle in the tikka masala spice mix, then add the maple syrup and coconut oil. Season with a little salt and black pepper. Mix everything well so the spices and liquids coat the vegetables evenly. I find that mixing thoroughly at this stage really helps the flavors to develop as it cooks.

Cover and cook the curry in the slow cooker. For high heat, cook for 3½ hours, for medium heat cook 5–6 hours, or for low heat allow 7–8 hours. Halfway through, you can give everything a gentle stir if you'd like. At the end of the cooking time, check that the cauliflower is fork-tender but still has some bite. If it needs a little more time, continue cooking to your preferred texture. Personally, I prefer the cauliflower to be just soft enough so it doesn't fall apart.

Once the cauliflower is ready, stir in the fresh spinach. The heat from the curry will wilt the spinach quickly, so just fold it in until it's just incorporated. Taste the curry and adjust the seasoning with more salt or pepper if necessary. Depending on the acidity of your tomatoes or the heat of your spice mix, add an extra teaspoon of maple syrup or sugar to balance the flavors, if needed. For a flavor boost, I like to add a squeeze of fresh lemon juice right before serving.

Ladle the hot tikka masala curry into bowls. Scatter chopped cashews or flaked almonds over each serving right before eating. Serve the curry with freshly cooked rice and warm naan breads for a complete meal.