Preheat the oven to 400° F. Using a fork or a sharp knife, carefully poke holes around the outside of the spaghetti squash. Microwave it for 5 minutes, then slice it in half lengthwise, scoop out the seeds and discard. *You might want to use an oven mitt to protect your hand*
Spritz the inside of the spaghetti squash with a thin layer of olive oil, and place each half cut side down on a baking sheet and bake for 30-35 minutes or until you can easily pull the strands with a fork.
While the squash is cooking, prepare the filling: add the ricotta cheese, parmesan cheese, Italian seasoning, lemon juice and spinach to a large bowl and mix until fully combined.
Also while the squash is cooking, prepare the meat sauce: heat a large pan on medium-high heat and sauté the garlic and onion until the onion begins to soften. Then add the ground turkey (or ground meat of your choice) and cook for 6-8 minutes or until fully cooked. Add the marinara sauce, season with salt and pepper to taste, and simmer for 5-10 minutes.
Remove the squash from the oven, flip it over and let it cool for 5 minutes. Then pull at the strands with a fork and place them in the mixing bowl with the filling. Add the spinach, and toss everything together until it's fully combined.
Add the spaghetti squash filling back into the "boats", divide the meat sauce between each one, top them with mozzarella cheese, and bake for 10 minutes or until the cheese is melted and bubbly. Garnish with fresh chopped basil and toasted panko, and serve.
Toasted Lemon Panko:
Heat a non-stick pan with 1 tbsp of olive oil on medium-high heat (I like to use the pan I am going to use for the meat sauce), then add the panko in a flat layer on the pan. Let it toast for 2-3 minutes on one side, then toss it around the pan and toast for another 1-2 minutes until it is golden brown. Mix in the lemon zest and transfer to a small bowl until you're ready to use it.
Spaghetti squash timing instructions are based off of a 4 pound spaghetti squash. If yours is larger, adjust the time as necessary. I recommend an extra 1-2 minutes in the microwave for each pound over 5 and an extra 5 minutes in the oven per pound.