Lightly spray slow cooker with cooking spray. Place onion, mushrooms, and garlic in the bottom of the slow cooker and then place the chicken thighs on top.
In a medium size bowl mix together the tomato paste, Merlot, tapioca, sugar, basil, salt, and pepper. Pour mixture over the chicken, cover, and cook on low for 5-6 hours or until chicken is tender.
Serve over pasta sprinkled with Parmesan cheese.
Notes
¼ cup chicken broth can be used in place of the Merlot.