In a non-stick pan, with no grease, fry the magret on the greasy side (medium
high flame) for 10 minutes ; empty some grease from time to
time to leave only the amount of 2 tablespoonsoons.
Turn it and fry the other side with the coarsely ground pepper for 5 to 8 minutes (depending on its thickness and how rare you like it). Take it out from the pan (keep it warm) and deglaze the pan with the Cognac which you need to heat and flambé...
Then mix with the sour cream, put the magret back in for 2-3 minutes then slice the magret and serve with the sauce.