01 - Place chicken thighs in the bottom of the slow cooker in a single layer, ensuring even distribution for consistent cooking.
02 - In a medium bowl, whisk together basil pesto, ranch seasoning mix, chicken broth, heavy cream, and grated Parmesan cheese until fully incorporated and smooth.
03 - Evenly pour the prepared sauce mixture over the chicken thighs, ensuring each piece is adequately coated.
04 - Cover and cook on LOW setting for 4 to 6 hours, or until chicken reaches internal temperature of 165°F and is tender throughout.
05 - Transfer chicken to serving platter, spoon remaining sauce over the top, and garnish with chopped fresh basil and additional Parmesan cheese if desired.