With a sharp knife, slice the squash in half. If the squash is too tough, puncture in several places forming a dotted line around the squash. Microwave for 3-5 minutes to soften. Allow to cool before cutting in half.
Scoop out the seeds, brush with oil, and sprinkle with salt, and pepper. Bake for 40-45 minutes, or until a fork can easily pierce the skin.
Meanwhile, in a pan combine oil, garlic, and onion over medium heat, and sautè until onions are translucent.
Add mushrooms and cook for 3 minutes. Add the broccoli, asparagus, squash, tomatoes, salt, and pepper and cook until almost cooked through.
Add the milk/ milk alternative until warmed through. Add the vegetarian Parmesan and mix until evenly spread throughout vegetables. Add the lemon juice and stir to combine.
Remove squash from the oven, with a fork pull at the edges to produce that stringy “spaghetti” quality.
In the pan combine “spaghetti” with vegetables. Return to the squash and top with Parmesan.