Set the oven rack to the middle position. Heat oven to 400ºF (204ºC).
Wash and dry the squash. Carefully use a sharp chef’s knife to cut the squash in half down the middle and then use a spoon to scoop out the seeds.
Place the squash cut-side down, trim off the stem and the bottom root side. Use a rocking motion to cut it into 1-inch thick wedges.
In a large bowl, toss together the squash slices, olive oil, salt, and pepper. Place the pieces in a single layer on a foil-lined rimmed baking sheet.
Roast for 15 minutes, then flip them over. Roast until the squash is fork-tender, about 10 to 15 minutes.
In a small bowl, combine maple syrup, soy sauce, and ground ginger. Brush on the roasted squash slices. Place in the center of the oven and broil on high until the surface lightly browns, about 2 to 3 minutes. Flip over, brush the other side with the sauce, broil for 2 to 3 minutes.
In a small nonstick pan, toast sesame seeds over medium heat until lightly browned, about 1 minute.
Top roasted kabocha squash with toasted sesame seeds and serve warm.
Make it GLUTEN-FREE: Substitute the soy sauce for coconut aminos or gluten-free tamari.