Years ago, I developed a wonderful challah recipe that uses butter in the dough, about 1/4 cup of butter to 4 or 5 cups of flour. I like butter in bread dough because it adds flavor and moisture, and it extends the keeping quality of the bread.
I am invited to somebody's house who is more strictly kosher than I am, so I must make a pareve challah. That means I have to replace the butter with something non-dairy. I thought about a neutral oil, such as safflower. I also thought about margarine.
Being a butter-lover, I am totally unfamiliar with the margarine market these days. Are there any credible margarines that taste fine in baked goods, or should I just stick with a vegetable oil? I don't want to add extra egg yolks, because I don't like challah that's too eggy.
Advice is appreciated!