Just serve it plain, and put it in the fridge for about 10 or 15 minutes before serving (or if it's in the fridge, take it out before serving so it's at cool room temp). Depending on the brand it may or not be seasoned so you may need to add cracked pepper and some fine sea salt. Check the label or taste it first.
Or you can cut it about 1/4-1/2 inch thick, and lightly sear it in a small amount of butter.
Serve this with very thin dry toast (crostini from a baguette, usually, with no oil or butter on it). Or, you can serve it as a first course with a red wine reduction sauce.
Lucky you, indeed.
I would recommend you serve it with something sweet.
At Christmas we served it with thin walnut toasts and a recipe of my own invention "Caramelized, Vanilla Scented, Bartlett Pear Compote"
3 Bartlett Pears, peeled, cored and diced into tiny cubes
1/3 cup of sugar
1/3 vanilla pod
1 1/2 cups of water
Halve the vanilla pod lengthwise and scrape out the seeds into a small non-stick saucepan. Add the remaining pod with the rest of the ingredients and bring to the boil. Reduce to a simmer and leave, approximately 30 minutes, until the liquid has reduced and the mixture starts to caramelize. From herein, continue to stir every 30 seconds or so, for the next 10 minutes, until all of the fruit is sticky with a golden brown caramel colour.
Traditionally in France it might be accompanied by a glass of a sweet wine like Sauternes too.
Long-time friends served me slices of foie gras on brioche toast with a rich warm something involving slivered mushrooms and caramelized onions -- a yummy combination -- and Sauternes on New Year's Day. The flavors worked very well together. (Their 16 year old son, having tasted it, said, "Is this on brioche? I think I would have used plain toast." I nearly fell off my chair.)
My favorite restaurant dish is pasta with a meaty ragou and shaved frozen fois GRAS on top. I'm thinking of making a wild mushroom pasta and shaving fois gras on top but am not sure. Has any tried tried this? I have had it on gingerbread and have enjoyed it as well. How about fully melted in mashed potatoes?