To make the sauce, place the egg whites, yoghurt, oil, salt and soda water in a jug or bowl and whisk until combined.
Preheat the oven to 360° F (180° C).
Lay one piece of phyllo sheet on the bottom of a lightly greased baking dish, the size of 9 ½" x 13" x 2 ¼" (24cm x 33cm x 6cm).
Drizzle on 1-1 ½ tablespoon of the sauce, and then spread it evenly using a brush.
Lay another sheet of filo on top and then drizzle some more sauce, spreading it evenly. Repeat until you used half of the phyllo sheets.
Place the meat and spinach filling on top of the last phyllo sheet and spread it evenly.
Layer the remaining phyllo sheets on top of the spinach and meat filling repeating the same process as before until the phyllo sheets are used up.
Carefully cut the phyllo pie into 12 equal squares using a sharp knife.
Whisk the egg yolks into the remaining sauce and then pour it evenly on top of the pie. Sprinkle on some sesame seeds and/or nigella seeds.
Place the pie into the preheated oven and then bake it for 35 to 40 minutes, until it is golden and crispy.
Let the Egyptian Goulash rest for 10-15 minutes before serving.