Prepare a mixture as follows: Chop separately 250 g (9 oz) each of fillet of beef and beef suet well cleaned of connective tissue. Cook 150 g (5½ oz) chopped onion in a little butter, add the beef and suet and cook until the meat is lightly brown.
Season with salt, pepper and nutmeg and mix with 2 tbs of thick Sauce Béchamel; allow to cool.
Prepare some noodle paste and make into 6 cm (2½ in) square Raviolis using the prepared mixture and cutting them out with a fancy pastry wheel. Poach the Varenikis in boiling salted water for 15 minutes, drain well and serve in a deep dish sprinkled with melted butter.