Sauté the onion and carrots on medium high heat in 2 tbsp butter for 5-6 minutes, until soft and starting to brown. Add corn, a little salt and pepper, stir to combine and sauté 3-4 minutes. Remove corn mix from the pan and set aside. Add remaining butter in sauté pan followed by the zucchini, squash and peas. Cook 5-6 minutes, stirring occasionally but not continuously so the veggies brown a bit. Add garlic and adjust seasonings to taste with a little more salt and pepper. Sauté an additional 2-3 minutes to allow the garlic to cook and mellow a bit.