First, preheat the oven to 450 degrees Fahrenheit. Coat 1 large baking sheet or 2 medium-sized baking sheets with olive oil cooking spray.
Then, add the sliced summer squash, zucchini, and red onion to a large bowl. Add in the thyme, oregano, olive oil, salt, and pepper to the vegetables. Then stir to cover the vegetables evenly.
Transfer the vegetable mixture to the baking sheet(s), spreading evenly. Then put the vegetables in the oven on the center rack.
Roast the vegetables until they are tender and golden brown. Flip the vegetables 1-2 times to help them cook evenly. Roast vegetables for 25-30 minutes.
Notes
Tips
Coat the vegetables evenly with olive oil and seasonings, so every bite has an amazing flavor.
Also, flipping the vegetables at least halfway through cooking will prevent one side from becoming overcooked.
If you have other vegetables on hand, such as bell peppers, you can add these for flavor and color!