Preheat the oven to 400°F and lightly grease a 9×13-inch baking dish.
Slice the zucchinis in half lengthwise and use a spoon to scoop out the centers, leaving a ¼-inch shell. Arrange the zucchini shells cut-side up in the baking dish and season with salt and pepper.
In a skillet over medium heat, cook the ground turkey until fully browned, about 5 minutes. Stir in the marinara sauce and let it simmer for 2 minutes.
Fill each zucchini boat with the meat mixture, mounding it slightly, then sprinkle the tops with shredded cheese.
Bake for 20 minutes, or until the cheese is melted and bubbly and the zucchini is fork-tender. Serve warm.
Notes
Broil for 1–2 minutes at the end for a crispy cheese top.
Use any marinara sauce you love! Bonus points for veggie-rich or low-sugar options.