Golden Greek Chicken Pie (Kotopita) with Creamy Filling

Method

1. Rinse the chicken well and place it in a large pot. Add enough water to cover it, along with the sliced onions and a good pinch of sea salt. Bring to a boil, skimming off any foam that rises to the surface with a slotted spoon. Cover and simmer for about 40 minutes, until the chicken is fully cooked.
2. Remove the chicken from the pot and let it cool slightly; reserve the cooking liquid (the broth). Once cool enough to handle, discard the skin and bones, and shred the meat into thin strips.
3. Meanwhile, prepare the béchamel sauce: In a large saucepan, melt 5 tablespoons of the butter. Whisk in the flour and cook for a minute to form a paste. Gradually add the warmed milk, whisking constantly. Then pour in 1 1/2 cups of the reserved chicken broth and continue whisking until the sauce thickens slightly. Remove from heat and stir in the grated cheese, eggs, nutmeg, salt, and pepper. Fold in the shredded chicken, chopped ham, and bacon.
4. Melt the remaining butter. Brush a baking tray (about 35x25 cm) with some of the melted butter. Unroll the phyllo sheets; you'll need 8 sheets for the bottom layer.
5. Layer the phyllo sheets one by one in the tray, brushing each generously with melted butter. Spread the chicken filling evenly over the phyllo, smoothing the top with a spatula. Fold the overhanging phyllo edges over the filling.
6. Top with the remaining 4 phyllo sheets, brushing each with butter. Trim any excess phyllo with a knife if desired, and roll the edges to seal. Brush the top with butter or oil, sprinkle with a little water, and scatter sesame seeds over. Use a knife to poke a few holes in the top.
7. Bake in a preheated oven at 350°F for 50-60 minutes, until the phyllo is crisp and golden. Let it cool slightly before serving.