In a large bowl, combine flour, sugar, salt, and yeast. Mix thoroughly.

Warm the milk slightly (not above 110°F/43°C) and mix with melted butter. Add to dry ingredients.

Beat in the egg and knead until a smooth, elastic dough forms. Cover and let rise for 1 hour, until doubled in size.

Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.

Roll the dough into a rectangle about 1/2 inch thick. Spread jam evenly over the surface, leaving a small border.

Fold or roll the dough gently to encase the jam and transfer to prepared baking sheet.

Let the dough rest for another 15 minutes to rise slightly.

Brush the top with melted butter and sprinkle with sugar.

Bake for 20-25 minutes until golden brown. Remove and let cool slightly before slicing.

Serve warm or at room temperature. Optional: dust with powdered sugar before serving.