In an 11 to 12 inch skillet on medium, heat 1 TBSP oil. Add onion and cook, stirring often, for 4 to 5 minutes. Add finely diced zucchini and cook, stirring often, for 3 to 4 minutes until slightly softened. Add mushrooms and cook, stirring occasionally, until all vegetables are tender and any liquid is absorbed, about 5 minutes. Remove from heat and season with 1/4 tsp. salt, 1 tsp Italian herbs and 1/8 tsp pepper. To a medium mixing bowl, transfer 1 cup vegetable mixture and cool completely. To a small saucepan, transfer remaining 1 cup mixture and set aside.