This brownie recipe (from this book) calls for eggs, beaten. I'm not entirely familiar with US recipes. What does it mean that the eggs have to be beaten? Is it sufficient to do this lightly with a fork or maybe they'd be better beaten using food processor?
The eggs should be beaten until roughly homogeneous; that is, there should be no "pieces" of unmixed egg white left. (If left in, those pieces would cook and harden, leaving you with, essentially, pieces of boiled egg in your brownies.) With some eggs there will be small strings of connective tissue from the egg that tend to float to the surface and appear as (slightly lumpy) bits of the white; these may be picked out with a fork, but they're unlikely to be noticeable in brownies.
Assuming you're adept with a fork, beating an egg or two shouldn't take more than 60 seconds.
BTW: In this recipe, there's no fundamental reason to beat the eggs before you add them to anything else. As long as they're thoroughly mixed in before you add the flour and other dry ingredients, you'll be fine.