1. Set the oven rack in the middle position and heat the oven to 425 degrees. Scrub but do not peel the squashes, trim ends and cut in half lengthwise, then seed and slice into 1/3-inch half-moons, and set aside.
2. In a small bowl, stir the ground fennel, coriander, and cumin with the brown sugar, paprika, cinnamon, and allspice to combine.
3. In a large bowl, toss the squash and oil to coat. Add salt and pepper to taste, add spice mixture, and toss again to distribute the seasonings. Line a large rimmed baking sheet with foil, spread the squash evenly in a single layer, and roast until well browned on the bottom, about 20 minutes. Remove the squash from the oven, cool to warm or room temperature, and serve.
Makes about 60 pieces