Turkish Savory Cookies with Mahlab

Soft, buttery Turkish savory cookies flavored with mahlab and topped with nigella seeds.

Ingredients

220 g	butter (half-melted)
1/2 чаша	oil (cup of 150 ml capacity)
2 броя	egg whites
2 ч.л.	mahlab
1 ч.л.	baking powder
4 ч.л.	powdered sugar
1 1/2 ч.л.	salt
2 с.л.	apple cider vinegar
4-5 чаши	flour (start with 4 and add the rest gradually; author used 4 1/2)
2 броя	egg yolks, beaten (for brushing)
—	nigella seeds (to sprinkle)

Mix all the ingredients for the dough until homogeneous. It comes out very soft and greasy.
Tear off pieces of the dough and shape small balls (3 cm). Arrange them in a tray on greased baking paper (spaced apart from each other).
Brush them with yolk and sprinkle with nigella seeds.
Bake in an oven preheated to 175 degrees with fan. The baking is not long, watch them.