Remove the seeds from the bell peppers and chop the bell peppers into 1-2 inch pieces. Slice the zucchini into ⅓ inch slices. Cut the baby bella mushrooms in half if they are large.
Toss all the vegetables and the chopped bacon into the prepared baking pan. Season with salt and pepper, if desired. Bake for 15-20 minutes, or until the bacon is fully cooked and crispy and the vegetables are roasted to your liking. Carefully transfer to a large dish lined with a paper towel to absorb the bacon grease.
Notes
I did not need salt for this recipe because the bacon gives enough saltiness to the vegetables, but feel free to use a little if you like!