Poached chicken breasts or leftovers from a rotisserie chicken work beautifully in this recipe. Slideshow: More Curry Recipes
Heat the olive oil in a large skillet over moderately high heat. Add the onion and ginger and cook, stirring occasionally, until slightly softened, about 5 minutes.
Add the curry powder, mustard seeds, cumin and turmeric and cook, stirring, until fragrant, about 30 seconds. Add the cauliflower and stir to coat with the spice mixture. Add 1/2 teaspoon of salt and 1/2 cup of water to the skillet and cook, stirring occasionally, until the cauliflower is crisp-tender, about 5 minutes. Add the carrots and cook until just tender, about 3 minutes, adding a little more water if the mixture looks dry.
Stir in the chicken and spinach and cook, stirring, until the chicken is heated through and the spinach is wilted.