Only if it comes from a kosher animal.
_________
Even if the liver comes from a kosher slaughtered animal, it still has to be kashered once you get it home. To do this, you have to grill it under high temp to sear off excess blood. Roasting the liver or cooking it anyway before doing the grilling step will render it treif.
No, of course not. Most liver is not kosher, just as most meat is not kosher.
cod liver oil
Liver
mutza chopped liver pate, vegetable plate, various salads, soups
The goose is a kosher bird, and the liver is a potentially kosher part of its body. So IF the goose is properly slaughtered and inspected, and IF its liver is removed and properly cooked, then the liver may be eaten. As far as foie gras is concerned, I'm no expert, but I do see a couple of problems: 1). The usual methods of fattening the goose with gavage might well be prohibited by the laws either in favor of kashruth or against cruelty to animals. 2). The only acceptable method of cooking liver for kosher consumption is thorough broiling, which might render it unusable as foie gras. That said, I'm sure that there are large numbers of Jews who eat foie gras. But I have some doubts that those who keep kosher do.
A recipe in which liver is wrapped in bacon is called rumaki. Rumaki is usually served as an appetizer. For diners who require kosher food, the liver can be wrapped in pastrami.
It is kosher so long as it is certified kosher.
Fox meat is not kosher. See:More about what is and isn't kosher
It needs to be cooked in a kosher vessel and have kosher ingredients. If purchased, it (or the bakery) should have kosher-certification.
Yes and no. There are many recipes that can be made kosher with kosher substitutes.
Delicatessen places serve kosher food. And if you are talking about 'deli' food, it is usually kosher. _______ Delis are only kosher if they're kosher certified. Most delis aren't kosher.
Yes! You don't need a kosher cookbook. Just remove the non-kosher ingredients.