This mildly sweet and deliciously flavored, fragrant bread is a special treat after a long Lenten season. It is especially good toasted and buttered. Mix Ingredients: Place 5 cups of flour in a large bowl. Set 1 cup aside to be added as needed if the dough is too soft. Place the mistika and 1 tsp sugar in a mortar and pestle and crush to a powder. Or place them between 2 layers of plastic wrap and slap sharply several times with the flat side of a large knife blade. Stir the mistika, mahlab, sugar, salt and yeast into the flour. Make a well in the center of the flour and add the milk, butter, egg and vanilla, working them in until all is incorporated. Knead Dough: Place the dough on a lightly floured surface and knead 5 to 7 minutes until smooth and elastic. The dough should be fairly soft. The kneading can also be done in an electric mixer. Place the dough in the mixer bowl and attach the dough hook. Knead for 3 to 4 minutes on low speed, until smooth and elastic. Stop a couple of times to push the dough down from the hook. With either method, if the dough is sticky, dust lightly with flour as needed. Place the dough in a bowl and cover with a cloth and then with a thick towel. Set it aside in a warm, draft-free place to rise until doubled in size, 50 to 60 minutes.   Shape Bread: When the dough has risen, punch it down and knead out the air bubbles. Cover and let the dough rest for about 10 minutes and then divide it in half. To make 2 braided loaves: divide each half into 3 parts and roll each part into a rope about 10 inches long. Braid the three ropes together and pinch the ends to seal. Turn the pinched ends under. Repeat with the other half of the dough. To make round loaves: simply shape each half of the dough into a smooth ball. Place the shaped loaves on the baking tray. Cover with waxed paper or parch- ment and then with a towel sprayed lightly with water. Set aside in a warm, draft-free place to rise until almost double, about 35 to 45 minutes. This is a rich, sweet dough and takes longer than other doughs to rise, so be patient.   Bake Bread: When the dough is almost ready, preheat the oven to 325 degrees. When the bread is ready to bake, prepare the glaze by beating the egg and water in a small bowl. Dip your fingers in the glaze and gently spread it over the surface of each loaf. Sprinkle each loaf with 1 Tbsp sesame seeds. Bake for 40 to 50 minutes until browned. Transfer to a cooling rack. After the bread has cooled for 20 to 30 minutes, cut a small hole in the center of each loaf and press in the red egg.