Put lukewarm milk, yeast, and sugar in a stand mixer bowl, then whisk well. Let it sit for 5 minutes.

Combine bread flour and cake flour, and add to the milk mixture. Add salt and milk powder, and start the mixer kneading with a dough hook at medium speed.

When the dough is becoming a ball (after about 8 minutes), add soft butter and knead for another 4-5 minutes until the butter is completely incorporated. Cover with plastic, and leave in a warm place about 1 hour until the dough has doubled in size.

Take the dough and push gently to deflate the gas from the dough. Put onto a cutting board, and cut into 6 equal pieces about 2.5oz (or 70g) each. Flatten and fold the dough three times, like a letter, and repeat 3 times. The folded dough should look like soft squares. Let them rest for 15 minutes covered.

Place a dough square on a cutting board. Roll out the dough with a rolling pin to 7" x 4" (18 cm x 10 cm). From a long edge, fold about 1/3 of dough toward the middle and press. Form the other long edge, fold 1/3 of dough toward the middle and press. Then finally fold and press the long edges together to make a long log. Pinch and tuck in the ends. Repeat for the rest of the dough.

Place shaped dough logs on a baking sheet lined with parchment paper, leaving 2" (or 5cm) space between the dough. Brush egg wash (the mixture of egg with a pinch of salt) on the surface of the dough. Leave them to double in size, about 1 hour.

Bake in a preheated oven at 400F(205C) for about 9-10 minutes until they brown.

If you wish, make a slice in the middle of the bread, and sandwich apricot jam and buttercream.