Pulse cauliflower florets in a blender or food processor until broken into small pieces about the size of rice.
Heat butter in a large frying pan over medium-high heat. Add cauliflower rice, garlic, cumin, coriander, garam masala, turmeric, ginger and cayenne pepper. Cook, stirring occasionally, until cauliflower is softened, about 10 minutes. Season with salt and pepper.
Remove pan from heat. Serve with lime wedges and freshly chopped coriander.