To make the dough, combine the flour and salt in a large bowl, stir in the water and egg and stir until you have a soft dough. Knead it for a few minutes, until smooth. Cover with a tea towel and let rest while you prepare the filling.
In a medium bowl, blend the lamb, onion, baharat, salt and pepper with your hands until well combined. Stir the garlic and salt into the yogurt and set aside or stash in the refrigerator.
To fill the manti, divide the dough into four pieces, and working with one at a time (keep the others covered with a tea towel), roll the dough out thin and cut into strips 1 1/2” wide, and again across, making 1 1/2” squares. (Or go 2” if they’re too small to handle.) Place a tiny amount of filling on each square and gather up the corners to meet in the middle, pinching down the seams to seal. (These can be filled in advance and frozen, or kept covered in the refrigerator until you’re ready for them.
To cook the manti, bring a large pot of salted water to a boil and drop them in; boil for 6-8 minutes, until tender. Remove from the pot with a slotted spoon.
Meanwhile, in a skillet set over medium-high heat, melt the butter and continue to cook it until it turns golden and smells nutty. Add the tomatoes to the pan along with the pepper and a pinch of salt and cook until the tomatoes break down and become thick and jammy.
Divide the yogurt between 4-6 shallow bowls and top with the manti, browned butter tomato sauce and a light sprinkle of sumac. Serves 4-6.