Preheat the oven to 450º F.
Whisk the flours, salt, and baking soda in a large bowl until combined.
Mix the yogurt and water together in a separate bowl. Create a well in the middle of the dry ingredients and pour in the yogurt mixture. Use your hands to scrape from the outside in to combine the dough.
Fold in the dates and pecans and turn out the dough onto a well-floured work surface. Knead lightly for a few seconds to bring the dough together, then pat into a smooth disk about 1.5" thick. If there are a lot of date pieces on top, poke them through the dough so they don't burn.
Use a sharp knife to score the disk in quarters, cutting all the way to the edges. Brush the top with milk and set on a baking sheet.
Bake for 15 minutes, then lower the oven temperature to 400º F. Bake an additional 30 minutes, or until the top is golden and the bottom sounds hollow when tapped.
Let cool until warm to the touch, then slice and serve with your choice of toppings.
