Preheat the oven to 400°F (200°C).
Cut the spaghetti squashes in half lengthwise and scoop out the seeds.
Brush the inside of each half with 1 tbsp olive oil and place cut-side down on a baking sheet.
Roast for about 40-45 minutes until the flesh is tender and easily shredded.
While the squash cooks, heat the remaining olive oil in a pan over medium heat.
Add minced garlic and sauté until fragrant, about 1 minute.
Add fresh spinach and cook until wilted.
Remove from heat and stir in chopped artichokes, cream cheese, mayonnaise, and Parmesan cheese until well combined.
When the squash is cool enough to handle, use a fork to scrape out the flesh into strands, leaving the skins intact.
Combine the spaghetti squash strands with the spinach and artichoke mixture.
Spoon the filling back into the squash shells and top with grated mozzarella.
Return the stuffed squash halves to the oven and bake for an additional 15-20 minutes until the cheese is melted and bubbly.
Serve warm and enjoy.