Place butternut squash on a cutting board, cut off both ends, and discard. This will help stabilize the squash when standing on the base.
Hold the squash in one hand, using a vegetable peeler in the other, and make long downward strokes just beneath the skin of the squash to remove the skin.
Using a sharp knife, cut down the middle of the squash. Using a spoon, remove the seeds and the membrane lining the cavity.
Lay the squash on the cutting board, cut slices, then cubes.
Place cubes on a prepared cooking sheet lined with parchment paper or sprayed with oil.
Spray with oil and roast in a preheated baking sheet at 400 degrees Fahrenheit for 40 minutes, may take longer depending on the sizes.