Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Slice the spaghetti squash in half lengthwise, scoop out the seeds with a spoon, and brush the inside flesh with half of the olive oil and a pinch of salt.
Place the squash halves cut-side down on the prepared baking sheet and roast for 40 to 45 minutes until the outer skin is easily pierced with a fork.
While the squash is roasting, heat the remaining olive oil in a large skillet over medium heat and add the ground turkey.
Cook the turkey, breaking it apart with a spatula, until it is browned and cooked through.
Stir the marinara sauce, garlic powder, dried oregano, sea salt, and black pepper into the skillet with the turkey and let it simmer on low for 5 to 7 minutes.
Once the squash is done, remove it from the oven and use a fork to scrape the flesh into spaghetti-like strands while keeping them inside the squash skin shells.
Divide the turkey marinara mixture evenly between the two squash halves, stirring slightly to incorporate with the strands.
Top each half with the shredded mozzarella cheese and place under the broiler for 2 to 3 minutes until the cheese is melted and golden brown.