01 - Place chicken thighs in the bottom of the slow cooker in a single, even layer.
02 - In a medium bowl, whisk together the pesto, ranch seasoning, chicken broth, heavy cream, and Parmesan cheese until thoroughly combined and smooth.
03 - Pour the sauce mixture evenly over the chicken thighs, ensuring all pieces are coated.
04 - Cover and cook on LOW setting for 4–6 hours, or until chicken is tender and reaches an internal temperature of 165°F.
05 - Transfer chicken to a serving platter and spoon sauce over the top. Garnish with fresh basil and extra Parmesan cheese if desired.