Cooking duck and keeping warm?

Duck breast should be medium rare IMO.

Take a good thing and make it bad is a sure way of missing the target. Aim to please but use a different weapon. A tough duck breast will not find its way through a woman's heart. You must use something tender, something succulent that melts her soul, like duck confit, or a love souffle.

Since it is fall in the Northern Hemisphere here, try a braise. That's easy, like a cassoulet style dish. Maybe braise duck legs and white beans with sausage or something. Just suggesting. Then again, she might be touched that you went through all the trouble. :)

Score the skin, give it a quick sear, then finish it in the oven. Use kosher salt.

Learning question: is rock salt meant for cooking? I thought it was for sidewalks and stuff. Not busting on T800- it's a serious question on jmy part.

I personally believe coarse kosher salt (uniodized medium-grain salt) is best for seasoning seared foods due to the size of the grain.

Rock salt, if you find it in the grocery or foods store is perfectly fine for cooking. It's just that the large size of the salt grains makes for pretty uneven seasoning if you're using it to crust a steak or something like that.

As for duck breast, I'm going to disagree somewhat with the anti-well done cadre due to my experiences of eating with/cooking for a mother who's never liked rare/raw foods and a lifetime of eating cantonese cooking (where every kind of meat, including duck is served well done).

Qs 1 & 2: Yes, you can finish it off in the oven. Preheat your oven when you sear off your breasts to 350 F and put the breasts in (either in an ovenproof pan or baking sheet) when sufficient fat has been rendered off from under the skin and when both sides are nice and golden brown. Use the finger test to determine the doneness and cook it to the doneness you want.

3: You can keep duck warm in the oven without destroying it, although if you're cooking duck breast in this manner you should treat it like a steak, let it rest on the cutting board about 10 minutes to allow the juices to redistribute before slicing and serving. If you really want to keep it in the oven, you need only turn it to around 150 F.

4: How large are your grains of rock salt? If they're about the size of the grains of pavement salt then I suggest you move down to fine sea salt, table salt, or kosher salt. Smaller grains will distribute the saltiness better for searing and you can ease up on it without underseasoning. Also if you're not already use your fingers to distribute the salt, it'll give you better control than shaking it out of a box or salt shaker.

As for the well-done question, does your girlfriend like well done foods because she doesn't want to see blood? Or is it because she likes the slightly chewy texture of well-done foods? If she is simply evasive of blood and you really want to make the duck then I suggest you slice the duck very thinly against the grain prior to serving: this will make the meat easier to eat. You can also add some stock, reduce the heat and simmer the breast slightly (skin side up... don't make the skin soggy) before finishing it in the oven.