Preheat the oven to 300°F. Slice the bread into small square cubes. Spread the bread out in a single layer on a large baking sheet lined with foil or a silicone baking sheet. Bake for about 30 minutes or until the bread is dried and crunchy. Remove from the oven, allow to cool for several minutes and then pour bread into a large bowl.
In a large skillet over medium heat melt the butter, add the onion and allow it to cook for about 3 minutes until soft and translucent. Add in the garlic and cook for an additional 30 seconds until fragrant. Pour this mixture over the dried bread.
Remove the turkey breast from the fridge. Pat dry with paper towels. Prepare the garlic herb butter by mixing all of the ingredients together in a small bowl. Use half of the butter on the turkey breast, rubbing into the skin.
Preheat the oven to 425°F. Heat a large oven safe skillet over medium high heat. Once heated place the turkey breast in the skillet skin side down. Sear the skin for about 2 minutes then move the skillet to the oven and continue baking at 425°F for 30 minutes.
While the turkey is baking, beat the eggs and mix into the stuffing mixture. Pour the stuffing into a large roasting pan. Once the turkey is done baking for 30 minutes remove from the oven, carefully use two towels to protect your hands and transfer the turkey breast into the roasting pan breast side up on top of the stuffing. Add the turkey thighs to the roasting pan on top of the stuffing as well. Coat the thighs with the remaining garlic herb butter. Take the time to ensure all the stuffing is under the turkey to keep it from cooking too much.
Reduce the heat in the oven to 350°F. Bake the turkey and stuffing for an additional 50-75 minutes, to where when you place a meat thermometer in the breast the temperature is at least 160-165. The thighs should be at 175 to 180.
Remove from the oven and allow the turkey to rest for about 20 minutes prior to cutting.
Stir the stuffing to mix with the juices from the turkey.