This Kale and Mushroom Paella is a vegetarian twist on the classic Spanish dish. It is packed with flavor from the saffron-infused rice, earthy mushrooms, and hearty kale. The dish is cooked in a large skillet, allowing the rice to develop a crispy bottom layer, known as socarrat. Serve this paella as a main course or as a side dish with grilled vegetables or a fresh salad.