Bring a small pot to a boil. While waiting to boil, combine all ingredients for the sauce, whisk together and set aside. Once water boils, add in the spinach for 30 seconds or until wilted and then transfer with a slotted spoon to a plate and gently squeeze out excess water. Set aside.

Heat a large skillet over medium-heat and once heated, add in the olive oil. Once oil heats, add in the onion, carrots and shiitake mushrooms and cover and cook for 5-7 minutes or until mushrooms are wilted and carrots have mostly softened.

Add in the zucchini noodles and toss for 2-3 minutes or until zucchini is cooked to al dente. Pour the noodle mixture into a colander and toss to let excess moisture drain out. Place the drained noodle mixture back into the skillet.

Add in the spinach and pour in the sauce. Toss to combine all the flavors and warm the sauce, about 1 minute. Transfer to plates and garnish with sesame seeds.