Yes, you can substitute plain table salt for sea salt. Sea salt is generally a smaller grind than table salt.

When you need substitutions, a great web site to check out is The Cook's Thesaurus. See the link below for more information.

-Grainlady

Here is a link that might be useful: The Cook's Thesaurus - Salt

Thank you! I have seen that site but forgot about it. I appreciate your help.

I made a break-apart cookie last night, that only calls for flour, sugar, unsalted butter, and coarse salt. It is supposed to have a slightly salty taste to it. So there are conditions under which you are probably better to have something more granular, and your recipe may be one of them.

Whether you use sea salt or kosher wouldn't be as much a difference as coarse salt vs. fine table salt.

Here is a link that might be useful: Salted butter break-ups