Dry-fry lamb over medium-high heat in a large flameproof casserole until lightly browned, 6 to 8 minutes; stir frequently. Add carrot, celery and leek. Cook 4 minutes; stir occasionally.
Add cider and stock. Bring to the boil. Reduce heat to low; cover and simmer until vegetables are tender, 20 to 25 minutes.
Meanwhile, heat oven to 200ºC. To make pastry topping, combine the flour, parsley, sage, salt and pepper in a medium bowl. Stir in sour cream; mix to make a firm dough. If dough is too dry, add 1 or 2 tsp milk. Roll out to 1.5 cm thickness. Cut into 16 triangles.
Add peas and bouquet garni to casserole. Arrange pastry triangles on top, covering the surface.
Bake until pastry topping is well risen and golden brown, 25 to 30 minutes.
on the menu
With all the vegetables, meat and pastry in the lamb cobbler, you need add very little to make a meal. You might start with a cream of pumpkin or spinach soup and finish with fresh fruit and a selection of your favourite cheeses.