Preheat oven to 375ºF (190ºC). Cut both the squash in half lengthwise, removing the seeds and setting aside. Trim ¼-inch from the stem end and bottom of each squash and discard. Slice each half into ½-inch slices.
Toss in 3 tablespoons of the olive oil and arrange in an even single layer on a baking sheet. Season with the ancho chili powder, salt and pepper.
Roast the squash for 20 minutes then flip each piece and continue roasting until golden brown and tender, about an additional 15 minutes. Remove and set aside.
While the squash is roasting, clean the membrane from the seeds and discard, rinsing the seeds until separated and clean. Pat dry with a paper towel and toss with the remaining olive oil. Season with salt and pepper and arrange in a single layer on a small baking sheet. Roast until dried and golden brown, about 15 to 20 minutes, shaking the pan occasionally.
Arrange squash on a platter and top with the roasted seeds, lime zest, queso fresco, cilantro leaves and pomegranate seeds (if using). Serve immediately.