In a large pot or Dutch oven, combine the chicken, onions, garlic, ginger, coriander, cinnamon, and saffron. Cover and let sit for 1 hour.
Stir in broth and salt. Place over high heat to bring to a boil. Decrease heat to medium low and simmer, pot still covered, until chicken is tender, about 1 hour.
Remove the chicken to a large bowl using a slotted spoon. Strain the broth into a large bowl, setting aside the onions.
Rinse the pot and add broth. Add lemon juice and bring to boil over high heat. Boil until there is 1 cup of broth left and reduce heat to low.
In a small bowl, beat together eggs and honey. Slowly pour into the broth, whisking continuously. Continue to whisk until the broth thickens and tracks from the whisk remain, about 5 minutes. Remove from heat and season with salt and pepper.
Chop the chicken into small pieces and add to the sauce. Stir in onions, thyme, and parsley.
Place rack in center of oven and preheat to 400 degrees Fahrenheit. Line a large baking sheet with foil. Brush a 9 inch round pan (2 inches tall) with melted butter.
Place one sheet of phyllo on work surface and cover remaining sheets with towel. Brush phyllo with butter and place across prepared round pan, hanging the ends over the edges. Brush second sheet with butter and place in pan perpendicular to first sheet, forming a cross. Brush third sheet with butter and place diagonally into pan. Brush fourth sheet with butter and place perpendicular to third sheet, forming an x. The pan should now be covered.
Cover the bottom with half of the almonds. Add the chicken mixture. Cover with remaining almonds. Fold in the excess phyllo.
Brush each remaining sheet of phyllo with butter, stacking them on top of each other on work surface. Use the bottom of a 10 inch pan to cut out a 10 inch circle from the phyllo. Place over the pie and carefully tuck the edges into the sides of the pan. Brush the top with butter and sprinkle with cinnamon sugar. Place the pan on the foil lined baking sheet. Bake in preheated oven for 20 minutes, decrease temperature to 350 degrees Fahrenheit, and bake for an additional 20 minutes. During baking, if the top becomes too brown, cover loosely with foil. Let rest 5 minutes and sprinkle with powdered sugar.
Cover a cutting board with parchment paper. Gently flip b'stilla onto cutting board and flip again onto serving platter. Slice into wedges and serve warm.