"This gluten-free, dairy-free recipe is a great way to eat pasta and get your vegetables too. Change up some of the optional ingredients or add meat for other delicious variations. Great way to use up vegetables before they go bad in your fridge. This recipe is very forgiving and hard to screw up. The amounts are just a guesstimate and do not have to be exact. I encourage you to play, eat, and enjoy!"
Bring a large pot of lightly salted water to a boil. Cook pasta in the boiling water, stirring occasionally until tender yet firm to the bite, 6 to 9 minutes. Drain.
Heat olive oil in a pot over medium-high heat. Cook and stir eggplant and zucchini in the hot oil until browned, about 5 minutes. Stir in 1/2 cup tomato sauce. Season with garlic salt and oregano. Cover and simmer until flavors combine, about 5 minutes.
Stir mushrooms and onion into the pot; cover and cook for 5 minutes. Add remaining tomato sauce and diced tomato. Cover and simmer until tomato begins to break down, about 5 minutes. Reduce heat to medium-low; simmer, stirring occasionally, until eggplant and zucchini soft, about 7 minutes.