In a stand mixer, combine all-purpose flour, bread flour, salt, and softened butter. Blend on low speed for about 3 minutes until everything is well incorporated and crumbly.

In a separate bowl, mix the active dry yeast, granulated sugar, and warm milk. Let it sit for 15 minutes until foamy, indicating the yeast is active.

Add the foamy yeast mixture and a large egg into the dry flour blend. Stir until all ingredients are fully mixed and everything is combined.

Knead the dough in the mixer for about 2-3 minutes until it becomes slightly sticky and firm. You want a smooth consistency.

Shape the dough into a ball and place it in a greased bowl. Cover it with a damp cloth or plastic wrap; let it rise in a warm place until doubled in size, around 45-60 minutes.

Once risen, divide the dough into 24 equal portions; shape each into a ball. Place them on a greased baking pan, spaced apart, and cover to let rise again for about 30 minutes.

In a mixing bowl, blend the softened cream cheese, powdered sugar, egg yolk, and vanilla until smooth and creamy. Chill in the fridge while the dough rises.

Create small wells in each risen dough ball using your fingers or a spoon. Fill these wells with your chosen fruit preserves and a spoonful of the cream cheese filling.

Preheat your oven to 350°F. Bake the kolaches for 17-20 minutes, until they are golden brown and fluffy.

In a small bowl, mix melted butter, powdered sugar, milk, and vanilla until smooth. Drizzle the glaze over the cooled kolaches for that sweet finishing touch.