In a large bowl, stir together the flour, salt, and mahleb.

In a medium saucepan, heat milk until hot but not boiling.

Add butter, shortening, and sugar to the milk, stirring until the sugar is dissolved.

Remove the saucepan from the heat and set aside to cool slightly.

Dissolve the yeast in 1/2 cup of warm water with a pinch of sugar to activate it.

Wait for the yeast mixture to become foamy, indicating it's active.

Make a well in the center of the flour mixture.

Add the eggs and the milk mixture to the well in the flour.

Pour in the activated yeast mixture.

Stir to blend the ingredients well until a dough forms.

Turn the dough out onto a lightly floured surface.

Knead the dough until it is smooth and elastic, about 8-10 minutes.

The dough should be slightly sticky but not dry.

Place the dough in a large greased bowl, turning to coat all sides.

Pat the top of the dough with a bit of oil to prevent sticking.

Cover the bowl with aluminum foil and then a clean dish towel.

Let the dough rise in a warm place for 2 hours, or until doubled in size.

Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius).

Break off small amounts of dough and shape into pretzels or braids.

Place the shaped rolls on a baking sheet lined with parchment paper.

Allow the rolls to rise for 30 minutes.

Brush the rolls with egg wash (beaten egg).

Sprinkle the rolls with sesame seeds and/or nigella (black) seeds.

Bake in the preheated oven for 20 minutes, or until golden brown.