Enchiladas are typically made from rolled up tortillas, but in this gluten-free, grain-free version, we're using spiralized sweet potatoes in layers, to make a lasagna-style enchilada casserole. Who doesn't love lasagna and enchiladas? This dish is packed with veggies and protein and saves well for meal prep and leftovers. The layers of enchilada sauce, sweet potato, spinach, black beans and chicken are delicious and make for a healthy weeknight meal. Depending on how you slice the casserole, you can make 6 giant slices or 12 slices. I recommend making 12 and serving with a yummy side salad or veggie, like some corn or string beans.
Preheat the oven to 375 degrees F. Coat a 9-by-13 inch baking dish with cooking spray and set aside.
Prepare the enchilada sauce. Heat the oil in a medium saucepan over medium-high heat. When the oil is shimmering, add the arrowroot powder and whisk until combined, about 1 minute. Add the tomato sauce, broth, chili powder, cumin, garlic powder and salt to taste.
Bring to a simmer, then reduce the heat to low and cook, stirring occasionally, until thickened, 15 to 20 minutes.
While the enchilada sauce cooks, spiralize the sweet potatoes. Trim the ends, then slice halfway through the sweet potatoes lengthwise, careful not to pierce through the center. Spiralize to yield chip slices. Set aside.
Spread 1/2 cup of the enchilada sauce on the bottom of the baking dish. Arrange a third of the sweet potato slices in a single layer, overlapping slightly to cover up any little gaps. Sprinkle half of the beans, half of the chicken, 1 cup of the cheese, half of the spinach and 1/2 cup of the enchilada sauce evenly over the sweet potato slices. Repeat, starting with a third of the sweet potato slices, then the remaining beans and chicken, 1 cup of the cheese, the remaining spinach and 1/2 cup of the enchilada sauce. Finish the casserole with the remaining sweet potatoes slices and spread the remaining enchilada sauce over top. Cover tightly with aluminum foil.
Bake the casserole for 40 minutes. Uncover and sprinkle with the remaining 1 cup of cheese. Bake until the cheese melts and the casserole bubbles, about 5 minutes. Let cool for at least 10 minutes, then top with the avocado and cilantro before serving.