Preheat your oven to 400°F. While it heats, wash the zucchini and cut each one in half lengthwise. Using a spoon or small melon baller, carefully scoop out the centers, leaving about 1/4 inch of flesh on the sides and bottom to create sturdy boats. Arrange the hollowed zucchini halves cut-side up in a 9x13 inch baking dish, spacing them evenly.

Heat a large skillet over medium-high heat. Add the ground turkey and diced onion, breaking the turkey into small crumbles as it cooks. Cook for 8-10 minutes, stirring occasionally, until the turkey is completely cooked through and no longer pink, and the onion is softened and starting to caramelize. I like to let the turkey sit undisturbed for the first minute or two to get some browning—this develops deeper flavor in the filling.

Sprinkle the garlic powder and dried oregano over the cooked turkey mixture and stir to combine. Pour in the marinara sauce and stir well to coat everything evenly. Simmer for 2-3 minutes, allowing the flavors to meld and the sauce to warm through. Taste and adjust seasonings if needed.

Spoon the turkey-marinara mixture generously into each zucchini boat, dividing it evenly among all eight halves. The boats should be well-filled but not overflowing. Sprinkle the Parmesan cheese evenly over the top of each boat—I prefer using Kraft Grated Parmesan because it creates a salty, slightly crispy crust when baked, which adds wonderful texture contrast to the soft zucchini.

Cover the baking dish tightly with foil and place it in the preheated 400°F oven. Bake for 20-30 minutes, until the zucchini is fork-tender and the filling is heated through. Remove the foil for the last 2-3 minutes if you'd like the cheese to brown slightly more. The zucchini should collapse slightly when pierced with a fork, indicating it's fully cooked.