Microwave the frozen spinach for 1 minute, then squeeze it dry.
In a saucepan, melt the butter with the olive oil and sauté the mushrooms and onion until tender (about 5 to 7 minutes), then add the thawed/drained spinach, chopped turkey meat, Rotel, cumin, ancho, cayenne, oregano, basil, cilantro (if using), and salt, and sauté for about 7 minutes.
Remove from heat and stir in the cream cheese and 1/4 cup sour cream until well combined.
Lightly pan spray a 9x13-inch oven dish; pour a little of the enchilada sauce into the bottom of the dish, about 1/4 cup, and roll the dish in your hands to coat the bottom with the sauce.
Place the flour tortillas between damp kitchen or paper towels and microwave for 45 seconds to soften.
Spoon a quarter of the enchilada filling in the center of each tortilla, then roll each (tucking ends in) and place seam-side-down in the oven dish.
Pour the remaining enchilada sauce over the completed enchiladas, dot with remaining 1/4 cup sour cream, then top with the grated cheeses.
Bake at 350 degrees F for 20 to 30 minutes, until cheese is melted, bubbly, and golden.
Serve with rice, beans, and garnish with guacamole.