Preheat the oven to 425 degrees F, adjust a rack to the center and line a baking sheet with foil and set it aside.Wash and dry the squash well. Then cut it in half, lengthwise, and use a spoon to remove the seeds and any stringy membranes.Now cut each half into approximately 1-inch slices, horizontally. Set aside on a plate.In a small bowl, mix the pecans with the brown sugar, chili paste, cinnamon, cumin, salt and olive oil.Rub one side of each squash slice with the pecan mixture and then place them on the foil-lined baking sheet, rubbed side down. (Not much will stick, and that's ok.) Then using all of the rest of it, add a thin layer to the top of each slice, about â…›-inch thick.Place one or two sage leaves under each slice, and then place the pan in the preheated 425 degree F oven for 15 minutes.Remove the pan from the oven and cover it loosely with foil and roast for another 15 minutes.Remove the pan from the oven again, and evenly distribute the butter between the top surfaces of each slice, directly on top of the pecan mixture.Place the pan back in the oven for another 5 minutes or so -- when it's done, the squash should be very soft, the pecan crust should be golden, and the butter should be bubbling a bit.Let it cool a bit on the pan and then arrange on a serving platter, and as you do so, gently remove the sage leaves from the bottom of each squash slice and use them as a delicious garnish.