01 - Preheat oven to 400°F.
02 - Cut zucchini in half lengthwise. Use a spoon to scoop out the flesh, leaving a ¼-inch thick shell. Reserve ½ cup of the scooped flesh and chop it finely.
03 - Arrange zucchini boats cut side up on a baking sheet. Brush with 1 tablespoon olive oil and season with salt and pepper. Roast for 15 minutes.
04 - Heat remaining olive oil in a large skillet over medium heat. Add onion and cook for 2 minutes. Add garlic, chopped zucchini flesh, and butternut squash; cook 8-10 minutes until squash is tender.
05 - Stir in black beans, chili powder, cumin, smoked paprika, and ¾ cup enchilada sauce. Cook for 2-3 minutes and remove from heat.
06 - Remove zucchini boats from oven. Divide the black bean and squash mixture evenly among the boats.
07 - Drizzle remaining enchilada sauce over stuffed boats and sprinkle with shredded cheese.
08 - Return to oven and bake 15-20 minutes until cheese is melted and bubbly and zucchini is fork-tender.
09 - Top with queso fresco, cilantro, avocado slices, and lime wedges. Serve immediately.