1. Preheat oven to 450.
2. Combine 4 tablespoons softened butter, 3 minced garlic cloves, 1/4 cup minced herbs, 1/2 teaspoon black pepper and 1/2 teaspoon salt in a small bowl. Use a fork to mash everything together until very well combined. Remove 2 tablespoons and put in another bowl to use for rolls. Set both aside.
3. Arrange 1 large thinly sliced onion in a cast iron pan or baking sheet. 
4. Place turkey on onions. Use fingers to carefully loosen skin from meat to form a little pocket. Season turkey all over with remaining 1 1/2 teaspoons salt.
5. Spread butter mixture (minus the 2 tablespoons you saved earlier!) all over turkey, including directly on the meat - that's what the little pocket was for. Don't worry if the butter doesn't spread evenly, little butter and herb pockets are great. Lift up turkey and put a few dabs under the meat and on the onions.
6. Drizzle the entire pan with 4 teaspoons oil, with half on turkey and half on any onions that aren't covered by turkey.
7. Place in oven and immediately reduce heat to 400. Roast for 35-45 minutes, until meat is fully cooked (165 degrees).
8. Let rest for at least 10 minutes before carving. Serve onions alongside turkey, or use for this kale side dish!

Garlic-herb rolls:

1. Preheat oven to 350 (or according to package or whatever recipe you're using)
2. Arrange dough on baking sheet.
3. Melt reserved 2 tablespoons garlic-herb butter and brush most on biscuits/roll dough.
4. Bake according to package/recipe directions. Drizzle remaining garlic-herb butter as soon as you remove from the oven!