Preheat oven to 400 F. Line a baking sheet with aluminum foil.
Pat dry squash with paper towel. Transfer into a large bowl. Add olive oil, salt, soy sauce, sugar and 7 Spice. Toss with a pair of tongs until the squash are evenly coated. Transfer onto the baking sheet. Make sure to leave some space between them, so they won’t be steamed and will crisp up nicely. Bake for 15 minutes. Flip, then bake for another 10 minutes, or until the surface is charred and the inside turns tender.
Serve warm or at room temperature.