For Filling: Melt the butter over low heat in a large saucepan. Add the celery, onion, and bay leaf, cover, and cook about 10 minutes, or until the vegetables are soft.
Sprinkle the flour over the vegetables, stir well to incorporate, then cook for about 5 minutes.
Stir in the chicken stock and the milk or cream. Cook the sauce over low heat for 15 minutes, stirring occasionally. Remove the bay leaf and add the Tabasco, salt, and pepper.
Stir in the chicken, potatoes, carrots, peas or beans, and dill. Keep the filling warm while you make the biscuit dough.
Biscuits: Preheat the oven to 220ºC . Sift the flour, baking powder, and salt together in a bowl. Make a well in the mixture and cut the fat into the dry ingredients. Add the milk and dill and stir the mixture with a fork for about a minute, or until the dough leaves the sides of the bowl.
Transfer the chicken and vegetable mixture to a 3 litre ovenproof casserole. Drop the dough over the filling with a large spoon, spacing evenly, to make six biscuits.
Bake for 20 to 25 minutes, or until the biscuits are lightly browned and the pie is bubbling. Serve hot.