Divide your pre-made dough in half, then grease the bottoms of two pans with olive out. Roll out each half of this dough into a circle that is at least 4 to 5 cm larger than the diameter. Transfer the dough to the pan leaving the excess to hang over the edges.
First, drizzle the olive oil in a pan, warm it over the medium heat and then place your diced onions inside. Cook for 3 to 4 minutes.
Once the onions are cooked, stir in the ground meat, allspice, salt, and coriander. Allow it to break down over medium heat until the juices begin to cook off. Then take it off of heat and allow it to cool.
After giving the stew some time to cook, mix in your tahini and vinegar. Whisk the mixture until it thickens and the color lightens, then add ½ cup of water and continue to whisk.
Add the tahini sauce and chopped chives to the meat and stir until everything is thoroughly combined.
To Make The Pie:
Divide your filling evenly between your two pans and then spread it to cover the base of the dough.
Next, fold the edges of the dough over the top of the filling to cover the periphery of the filling.
Then, Arrange your tomato slices in any pattern so that it covers the filling.
Your final step is to whisk one egg with 1 tbsp vinegar per pan and brush the edges of the crust and the top of the tomatoes. Sprinkle the crusts with sesame seeds and bake.
Preheat the oven to 350 F and place your Galette on the rack in the middle and allow it to cook for 30 minutes or until the crust is golden brown.