Heat the oven. Preheat to 425°F (220°C). Line a baking sheet with parchment for easy cleanup.

Prep the squash. Toss cubed butternut squash with 2 tablespoons olive oil, 1 teaspoon salt, 1 teaspoon cumin, 1 teaspoon chili powder, and 1/2 teaspoon smoked paprika. Spread evenly on the baking sheet.

Roast until tender. Bake for 25–30 minutes, flipping once, until the edges are caramelized and the cubes are fork-tender. Set aside and lightly mash about half of it for a creamy filling texture.

Sauté the aromatics. In a skillet over medium heat, warm 1 tablespoon olive oil. Add the diced onion and cook 4–5 minutes until softened. Stir in the garlic and cook 30 seconds until fragrant.

Wilt the spinach. Add the spinach to the skillet with a pinch of salt and pepper. Cook 1–2 minutes until just wilted. If using black beans, stir them in now to warm through.

Combine the filling. In a bowl, mix the roasted squash, spinach mixture, a squeeze of lime, and 1/2 cup shredded cheese. Taste and adjust seasoning. The filling should be savory with a hint of sweetness and spice.

Warm the tortillas. Briefly heat tortillas in a dry skillet or wrap in a damp towel and microwave 30 seconds to make them pliable. This prevents tearing.

Prepare the baking dish. Spread 1/2 cup enchilada sauce over the bottom of a 9x13-inch dish to prevent sticking.

Fill and roll. Spoon 1/3–1/2 cup filling down the center of each tortilla. Roll snugly and place seam-side down in the dish. Repeat with all tortillas.

Sauce and cheese. Pour the remaining enchilada sauce evenly over the top. Sprinkle with the remaining cheese.

Bake. Reduce oven to 375°F (190°C) and bake for 18–22 minutes, until the sauce is bubbling and the cheese is melted and lightly golden.

Finish and serve. Let rest 5 minutes. Garnish with chopped cilantro and a squeeze of lime. Serve with sour cream or Greek yogurt if you like.