Instructions:
Preheat the Oven: Set your oven to 325°F (163°C).
Prepare Dry Ingredients: Sift together the all-purpose flour and baking powder into a large bowl.
Mix Wet Ingredients: In a stand mixer with the flat beater attachment, combine the unsalted butter, granulated sugar, honey, egg yolks, whole egg, and a pinch of salt. Mix on low speed until you achieve a homogeneous cream.
Combine Dry and Wet Mixtures: Gradually add the sifted flour and baking powder to the wet mixture. Mix on low speed until the dough comes together and no dry flour remains. Avoid overmixing to prevent a tough texture.
Roll Out the Dough: Place the dough between two sheets of parchment paper. Roll it out into a large rectangle, dusting lightly with flour to prevent sticking. The thickness is up to your preference; a thinner dough will result in more layers when sliced.
Add Filling: Spread a thin layer of the plum and bitter orange jam mixture over the dough, leaving a small border around the edges. Sprinkle walnut pieces evenly over the jam.
Roll and Shape: Carefully roll the dough from the short side into a log, ensuring the seam is on the bottom. Place the rolled dough onto a baking sheet lined with parchment paper, tucking the ends underneath to form a ring or oval shape.
Brush and Bake: Brush the top of the dough with the reserved beaten egg and, if desired, sprinkle with coarse sugar. Bake in the preheated oven for 25-30 minutes, or until golden brown.
Cool and Serve: Allow the flatbread to cool slightly before slicing. Serve warm or at room temperature.
Variations and Tips:
Dietary Substitutions:
Gluten-Free: Use a gluten-free all-purpose flour blend in place of regular flour.
Dairy-Free: Replace butter with a plant-based alternative and ensure the jam is dairy-free.
Sugar-Free: Substitute granulated sugar with a sugar alternative suitable for baking.
Flavor Enhancements:
Add a teaspoon of vanilla extract to the wet mixture for added depth of flavor.
Incorporate a handful of dried fruits like raisins or figs into the filling for a sweet twist.
Storage:
Store any leftovers in an airtight container at room temperature for up to 3 days. Reheat in a low oven before serving.