Pat the fillets dry. Season well with salt and pepper. Fry in hot oil. Place on a tray and cook in the oven for about 3 hours. Set the roast set aside.
Wash the rosemary, pat dry, chop the needles. Finely chop the toast and nuts in a blender. Melt the butter, stir in with the rosemary and eggs. Season with salt and pepper.
Remove the fillets. Turn the oven up to 225 ° C.
Brush the fillets with the nut mixture and bake for 10-15 minutes.
Heat the roast. Pour in the sherry and 600 ml of water, bring to the boil. Stir in the beef base, reduce for 5 minutes. Stir in the crème fraiche, season to taste. If the sauce is too thin, it may be thickened with a sauce thickener.