Place a rack in the center of the oven and preheat to 425°F. Line a rimmed baking sheet with parchment paper.
Place the cubed eggplant in the center and sprinkle it with the salt and pepper.
Drizzle on the oil then IMMEDIATELY toss to coat the eggplant (the oil will start to absorb instantly, which is why I suggest seasoning it with salt and pepper first; if you forget and pour the oil on first, toss it immediately, then add the seasoning and toss again). Spread the pieces into an even layer, making sure they do not overlap.
Roast eggplant for 23 to 28 minutes, using a spatula to toss it at the 15-minute mark, then spread it back into an even layer. When cooked, the eggplant will be tender and lightly browned in places. Remove from the oven and toss once more. Serve hot or at room temperature.
Notes
TO STORE: Refrigerate leftover roasted eggplant in an airtight container for up to 5 days.
TO REHEAT: Warm up leftovers in a 350°F oven or skillet until heated through. You can also eat leftover roasted eggplant cold or at room temperature.