0 Preheat the oven to 400°F.
1 Cut the spaghetti squash in half lengthwise, scoop out the seeds with a spoon, and place the halves cut side up on a rimmed baking sheet. Bake for 45 to 60 minutes, until the strands of the squash easily pull away from the shells with a fork.
2 While the squash is cooking, make the meatballs: add the ground beef, onion, garlic, and seasonings to a large bowl, then work the mixture with your hands until the ingredients are fully incorporated.
3 Line a rimmed baking sheet with parchment paper, then form the meatballs into 1-inch balls and place on the baking sheet. Bake at 400 F for 18 minutes. Note: you can bake the meatballs at the same time as the spaghetti squash, just make sure to place the meatballs on the rack above the squash.
4 While the meatballs bake, add the olive oil in a pot over medium heat. Once hot, add the onion and garlic and sauté for 3 to 4 minutes, until the onion is translucent and the garlic is fragrant.
5 Add the remaining ingredients to the pot and stir to combine. Bring to a boil to cook the alcohol off the wine, then reduce the heat to medium-low and cook, stirring occasionally, for 5 to 7 minutes, until the sauce is bubbling and slightly reduced.
6 To assemble the boats: remove the spaghetti squash from its shell and toss the strands with the sauce, then scoop the spaghetti squash back into the shells on a rimmed baking sheet. Place the meatballs on top of the spaghetti squash, then sprinkle with the mozzarella cheese. Return to the oven to bake at 400 F for an additional 10 minutes, until the cheese is browned and bubbling.
7 Garnish with fresh parsley and serve!
