Start by placing the water, yeast, and a pinch of sugar in the bowl of a stand mixer. Mix to activate the yeast, then add the rest of the sugar, milk, egg, and margarine, mixing until the ingredients are combined.
Gradually add the flour and salt, mixing until a supple dough forms and cleanly pulls away from the sides of the bowl. Cover the bowl with plastic wrap and leave it in a warm spot until the dough has doubled in size.
Once the dough has risen, roll it out into a rectangular sheet. Spread the Olympus Tahini with Cocoa over the entire surface and sprinkle the chopped dates evenly on top.
Roll the dough tightly starting from the long side. Using a sharp knife, cut the roll lengthwise down the middle to separate it into two long strands. Carefully twist the strands together to form a braid, then cut the braid exactly in half.
Place the two braids into two greased loaf pans (or line the pans with parchment paper) and leave them in a warm spot for about 30 minutes to rise again.
Once they have risen, brush the surface with the egg wash and bake in a preheated oven at 180°C for 35 to 45 minutes, or until they are well browned.