Make the Filling

1. Mix the cheese filling ingredients thoroughly. Refrigerate at least three hours, while you are making the dough.

Make the Ekmak:

1. In the bowl of a stand mixer, add the sourdough starter and half of the water (145 grams). Mix on low speed until combined.
2. Mix in the all-purpose and whole grains flours, 3 tablespoons sugar, and 125 grams of water. Reserve 20 grams of water to add with the salt. Mix on low speed until thoroughly combined and there are no bits of flour. Cover and let rest for 30 minutes.
3. Gradually mix in the butter and incorporate using the dough hook on low speed until the butter is evenly distributed, about a minute. Cover and let the mixture rest for 20-30 minutes before adding the salt.
4. Add the salt, and 20-25 grams of water, and mix on low speed until thoroughly incorporated. If the dough is dry, you can add more water, a little at a time.
5. Turn the dough out onto your work surface and form into a ball. Place the dough into a large bowl, cover, and let rise 2-4 hours, at warm room temperature. Stretch and fold the dough 2 times during the first hour, every 30 minutes. Then, let the dough rest for 1-3 more hours.
6. After the dough has rested for several hours, proceed to baking or cover the bowl tightly with plastic wrap, and place it in the refrigerator to cold ferment overnight.
7. Preheat your oven to 425 degrees F with a rack in the upper third of the oven.
8. Line three baking sheets with parchment and lightly sprinkle each with flour. Deflate the risen dough and let rest for 10 minutes.
9. Divide the dough into 9 pieces and cover the pieces with plastic wrap. Let rest for 15 minutes.
10. Roll each piece into a round and place each onto a lightly floured work surface. Cover with oiled plastic wrap and let rest for 10 minutes.
11. Stretch each ball into a 6 inch round, re-cover with the plastic wrap, and let rest for 10 minutes.
12. Stretch each round into a 10 inch by 4 inch oval and spoon 1/3 cup of the cheese filling onto the dough.
13. Fold the dough to create “boats” and stretch the dough to about 12 inches long. Place the “boats” on the parchment lined baking sheets, 3 per sheet. Cover with plastic wrap and let rest for 10 minutes.
14. Spoon a tablespoon of the jam mixture in the middle of the cheese mixture. Brush the dough with the egg wash.
15. Bake the ekmak for 15 minutes one sheet at a time, turning the baking sheet half way through.
16. Let cool on the pan for 10 minutes on a rack. Sprinkle with powdered sugar and serve warm with honey, if desired.