Prick squash all over with fork and roast in oven for an hour or until it seems soft when you press on it.
Take it out and leave on counter until cool.
Meanwhile, brown turkey sausage in large pot with 1 tablespoon of olive oil, breaking it up into small pieces. When brown add onion and half of garlic. Cook until onion is transparent and add tomatoes breaking them up with a spoon. Partially cover and simmer over low heat for a couple of hours, stirring occasionally. Add salt and pepper to taste.
When squash is cool, cut it in half and scoop out seeds. Scoop out the rest of the squash and set aside in a bowl. Add rest of garlic to rest of olive oil in a big frying pan over medium heat. When the garlic becomes fragrant add spaghetti squash and sauté for a few minutes until the squash begins to brown. Add salt and pepper to taste.
Mix together ricotta, chevre, parmesan, egg, and half of mozzarella.
Preheat oven to 375 degrees and pour a ladleful of sauce in the bottom of a lasagna pan to coat. Add squash. Top the squash with the ricotta cheese mixture and top the whole thing off with the rest of the sauce and then the rest of the mozzarella. Bake for an hour until brown and bubbling all over. Let rest for 10 minutes or so and serve.