Add the olive oil to a pan or pot with high sides. Over medium heat, add the garlic and onions. Cook until lightly brown and translucent.
Add the crushed tomatoes, breaking up the large chunks of tomatoes with the back of a wooden spoon in the pan. Cook the tomato mixture until thicker and less watery (about 5-10 minutes).
Cut the mixed vegetables into 1/2 inch cubes or smaller. Add the vegetables and mushrooms. Cook for 15 minutes on medium-low heat.
Once all the mixed vegetables are cooked through, add the leafy green and cook for an additional 10-15 minutes. Add the red pepper flakes, salt, and pepper.
I enjoy this sauce with pasta and a sprinkle of grated cheese on top! You can also use letovers to cook an egg in for breakfast.