Start by rinsing the boneless turkey breast under cold water and patting it dry with paper towels.
In a small bowl, mix together the salt, black pepper, garlic powder, onion powder, thyme, and rosemary.
Rub the olive oil over the turkey breast, then evenly coat it with the spice mixture.
Place the seasoned turkey breast in the slow cooker. Pour the chicken broth and lemon juice around the turkey.
Cover the slow cooker and cook on low for 6 to 8 hours or on high for 3 to 4 hours, until the turkey is cooked through and reaches an internal temperature of 165°F.
Once cooked, remove the turkey from the slow cooker and let it rest for 10 minutes before slicing.
Serve the turkey slices with some of the cooking liquid drizzled over the top and garnish with fresh parsley.