Preheat oven to 425F. Cube the butternut squash. Toss squash with ½ tablespoon olive oil. Spread out on a large baking sheet. Cook 10 to 12 minutes, until just soft.
While the squash cooks, bring a large sauce pot of water to a boil. Cook the pasta according to package directions. Drain and set aside.
Whisk together broth, balsamic vinegar, maple syrup, and soy sauce in a small bowl. Set aside.
In the same pasta pot, heat remaining ½ tablespoon of olive oil over medium-high heat. Add the onions, garlic and mushrooms. Season lightly with salt and pepper. Cook 3 to 4 minutes, or until onions and mushrooms begin to release their liquid.
Add balsamic sauce to the pan and cook on medium-high 2 to 3 minutes, or until the sauce reduces by half and slightly thickens. Add the squash and cook another 2 to 3 minutes.
Remove from heat and toss in pasta, until incorporated. Divide among bowls and serve.