Flatten the steaks with a cutlet bat trim into rectangles, approx. 12cm × 10cm.
Season the slices of beef, divide the sausage-meat into ten equal pieces. Roll and place one piece in the centre of each slice of beef. Roll up and tie carefully with string.
Butter a braising pan and cover the bottom with the rest of the ingredients (carrot, onion, celery, bacon trimmings, bayleaf, thyme).
Heat in a frying-pan, season the paupiettes and fry quickly to colour. Remove and place on top of the vegetables in the braising pan.
Add the Espagnole and then sufficient stock to cover a good two-thirds of the way up the paupiettes. Bring to the boil, skim and season. Cover with a lid and place in a moderate oven at approx. 180°C and cook until tender (approx. 1½ hours).
Remove the paupiettes, discard the string, arrange them in earthenware dishes, cover and keep warm. Remove the fat from the sauce. Pass the sauce through a fine strainer into a clean pan, reduce to the correct consistency and adjust the seasoning.
Serve on top of Pommes Purée, then pour the sauce over the paupiettes and sprinkle with chopped parsley.
