Wash and peel the onion, then slice it in half from root to stem. Slice each half into wedges, about ¼ -½ an inch thick. (Wedges are also from root to stem.) Place these in the bottom of your slow cooker.

Combine the spices (salt, pepper, Italian herbs, garlic powder, and onion powder) in a small bowl.

Using a paring knife, carefully make shallow cuts all along the turkey breast - I made about a dozen slits on the top only.

Then cover the entire turkey breast (top and bottom) with the spice mixture.

Place the seasoned turkey breast into the slow cooker atop the onions. (Slits up!) Cook on low heat for about 3 hours and 30 minutes, or until the internal temperature reaches at least 165ºF. (You want to pull the turkey out of the slow cooker as soon as it reaches 165ºF otherwise it will dry out! At about the 3 hour mark, I use the extender on my thermometer to put it into the turkey without having to keep taking the lid off, and then I check it every 5-10 minutes so I can pull the turkey right away!)

If desired, you can serve right away while its warm (which is what I would recommend for Thanksgiving!). However, you can also thinly slice this for deli sandwiches! To make thin slices, I recommend refrigerating the turkey until it is completely cold. Then, using a very sharp knife, carefully slice the turkey as thinly as you’d like!