Preheat oven to 400°F. Grease and flour a 10-inch cast-iron skillet and set aside.
In a large bowl, whisk together all-purpose flour, baking powder, sugar, baking soda and salt.
Add chopped dates and walnuts and stir into flour mixture.
Make a well in center of the dry ingredients. Pour in the buttermilk. Stir to form a thick, sticky batter. Scrap into prepared pan, pushing dough into the edges of the pan.
Bake in preheated 400°F oven until golden brown and when a toothpick inserted in the center comes out clean; 25-30 minutes.
Let cool slightly in pan (about 5 to 10 minutes). Run a knife around the edges. Loosen edges and slide bread onto a cooling rack. Cool for at least 15 more minutes before cutting.
Place any uneaten slices in freezer (in freezer bag) and reheat in oven (foil wrapped) until warm.
