1. Preheat oven to 350°F. Spray 9×13 inch baking dish with cooking spray. Rinse zucchini and trim both ends.

2. Bring large pot of salted water to boil. Add whole zucchini and cook for 5 minutes to soften. Drain in colander and let cool enough to handle safely.

3. Cut each cooled zucchini in half lengthwise. Using small spoon or melon baller, scoop out pulp leaving sturdy shell about ¼ inch thick. Chop scooped pulp and reserve for filling.

4. Melt 1 tablespoon butter in large skillet over medium-high heat. Add minced garlic, chopped onion, diced mushrooms, reserved zucchini pulp, Italian seasoning, salt and pepper. Cook 5-7 minutes until vegetables are tender and moisture evaporates.

5. In microwave-safe bowl, melt remaining 2 tablespoons butter. Stir in Parmesan cheese, Panko breadcrumbs, and Cajun seasoning until well combined.

6. Add breadcrumb mixture to skillet with vegetables. Stir thoroughly to combine all ingredients evenly.

7. Divide filling among zucchini halves, mounding generously. Arrange stuffed zucchini in prepared baking dish.

8. Bake 30 minutes until zucchini is tender and topping is golden brown. Let cool slightly before serving to allow filling to set.