Cut all the ingredients in cube. Preheat oven to 425 F•/220C•
In the saucepan over medium heat, cook onions and leek in butter until soft. Add chicken, carrots, and peas.
Stir in flour, salt & pepper. Stir in chicken broth and milk. Add the bay leave. Simmer over medium-low heat until thick. Remove from heat and set aside.
Lightly grease a dish. Place the mixture in the dish.
Crust: -1 cup flour -2 tsp. baking powder -½ tsp. cold butter (cut in cube) -1/8 tsp. salt -1/3 cup milk
In a large bowl, combine flour, baking powder, salt, cold butter and milk. Form into a ball, roll out.
Place crust on top, make several small slits on the top to allow steam to escape. Use the extra crust make some decoration. Brush with egg yolk.
Bake in the preheated oven for 30 minutes, or until pastry is golden brown and filling is bubbly.
Cool for 10 minutes before serving.