To make the meat sauce. Heat the olive oil in a large skillet over medium - high heat. Add the sausage and onion and cook for 5-8 minutes. Until sausage is browned & onions begin to become translucent. Add minced garlic saute for 30 seconds before adding marinara. Simmer sauce while you prepare the ricotta & spaghetti squash
For the Spaghetti Squash: cut in half lengthwise, scoop out the seeds and discard. Place squash cut side up on a baking sheet.
For the Cashew Ricotta: place cashews in a blender with lemon juice & 1/4 C water. Blend until smooth. Open up the blender and mix in the dried basil.
Season the spaghetti squash with salt & pepper. Sprinkle half of the parmesan into the bottom of each squash, then evenly divide meat sauce among the squash cavities. Now spoon the ricotta over the meat sauce and spread it around. Top with the remaining parmesan cheese. Cover the squash loosely with foil.
Transfer to the oven and bake 30 minutes. Remove the foil and continue baking another 10 minutes or until the squash is tender and the cheese is golden brown on top.