Place 1 roughly chopped onion, 4 roughly chopped carrots and 4 roughly chopped celery stalks and 2 sprigs fresh sage in the bottom of your slow cooker.
Place your 6-8 pound bone in turkey breast on top of the vegetables.
Blot your turkey dry of any moisture with paper towels (this will help the butter/seasoning stick to your turkey).
Melt 4 tablespoons butter, and add the1 teaspoon poultry seasoning,1 teaspoon garlic powder, 1 teaspoon smoked paprika, 2 teaspoons salt and ½ teaspoon black pepper. Whisk to combine
Pour the butter and seasoning mixture over the turkey breast.
Cover and cook on low 6-7 hours or until a digital thermometer inserted in the thickest part reads 165℉.
Remove the turkey from the slow cooker and let rest 10 minutes before slicing.