1. Preheat the oven to 400 F. Line a baking sheet with parchment paper.
2. Stir the sourdough discard into the buttermilk until no traces of starter remain. Set aside.
3. In a separate large mixing bowl, whisk together the flours, baking soda, salt and sugar.
4. Using your fingertips or a pastry cutter, work the butter into the dry ingredients until the mixture resembles coarse crumbs and the flour feels coated in butter.
5. Toss the chopped dates in the flour mixture until they are evenly distributed.
6. Create a well in the center of the flour mixture. Pour half of the starter mixture in and begin gently stirring the mixture until it begins clumping together.
7. Pour the remaining starter mixture into the remaining dry bits of flour.
8. Knead the dough gently until no traces of dry flour remain, if your dough feels too sticky, cover the bowl with plastic wrap and let the dough rest for 15 minutes.
9. Dust a clean work surface liberally with flour. Turn the dough out on the floured surface.
10. Working with lightly floured hands, knead the dough 4 to 5 times until the dough feels cohesive and supple.
11. Shape the dough by gently dragging it across your work surface, while simultaneously rounding it into a tight ball with your hands.
12. Transfer the dough to the prepared pan, then using a bench scraper or knife, make two deep cuts through the center, dividing the dough into quarters to ensure the bread bakes fully in the center.
13. Bake at 400 F for 30 minutes, without taking the loaf out of the oven, turn the heat down to 350 F and continue baking for another 15 minutes or until golden brown and the center of the loaf registers 200 F when probed with an instant-read thermometer.
*While Medjool dates are high in natural sugars, they are low on the glycemic index thanks to a balanced amount of soluble fiber. The complex carbohydrates found in Medjool dates are digested at a slower rate, making them a source of dietary fiber and releasing energy to the body over a longer period of time.
