Pat the turkey breast dry
Season with salt, pepper, garlic powder, onion powder, and any herbs you like
Place sliced onions, carrots, or celery in the bottom of the crock pot if desired
Put the turkey breast in the crock pot, skin side up if it has skin
Add 1/2 to 1 cup of broth, water, or stock
Cover and cook on low for 5 to 7 hours or on high for 3 to 4 hours
Cook until the internal temperature reaches 165°F in the thickest part
Baste once or twice if desired, but keep the lid closed as much as possible
Remove the turkey breast from the crock pot and let it rest for 10 to 15 minutes
Slice and serve