Preheat the Blackstone grill over medium high heat (approximately 350 degrees Fahrenheit).
Remove the turkey breasts and pat them dry with paper towels and place them in a disposable aluminum pan.
Pour the melted butter on top of the turkey breast.
Season the turkey breast with the garlic, paprika, dried thyme leaves, salt and pepper.
Cover the pan with the foil and close the lid on the Blackstone grill.
Allow the turkey to cook for 15 minutes. Then rotate the turkey breasts a quarter turn and cook for 15 more minutes. Continue this process 2 more times until the turkey reaches an internal temperature of 165 degrees Fahrenheit.
Remove the turkey breasts from the grill, loosely cover with foil and allow the turkey breast to rest for at least 5 minutes.
While the turkey is resting, prepare the gravy on the Blackstone Grill.
Transfer 1 cup of the sauce from the pan to a small saucepan and stir in the chicken broth. Heat the pan on the Blackstone grill over high heat.
Heat until the mixture starts to boil slightly.
Combine the cornstarch and water together in a small bowl. Whisk the cornstarch mixture into the saucepan and heat for 3-4 minutes, stirring constantly until the sauce thickens to the consistency that you prefer.
Slice the turkey and serve with the gravy drizzled over the top and enjoy!