Preheat oven to 375F. If you're using bacon, cook it up first so you can crumble it in.
Saute onions in olive oil until they start to turn transparent. Add mushrooms and toss for a few minutes. Add fresh spinach (chop it up first) and toss it until it begins to wilt.
While that is cooking up, whisk together the eggs and the soy milk. Add salt, pepper and cheese (if using) and whisk some more. Crumble the cooked and cooled bacon and whisk some more. Add in the parsley and basil and, you guessed it, whisk again! Lastly, add the onion/mushroom/spinach mixture. Quickly whisk it in and pour into greased pan (either 9x9 pie pan, or small glass dish). Pop it into the oven and cook for 30-35 minutes until the edges are browned and crispy. Let cool for a few minutes and serve! Mmmm... It's even yummy as leftovers, if there are any.