Q&A for How to Cook Spinach

Spinach can be certainly be steamed. For detailed instructions on how to do so, check How to Steam Spinach

Yes. You will just need to put more milk in, so it replaces it better and it makes it more useful.

It could be, but it won't taste as good or have as nice a texture. Precooked spinach can be heated in a microwave, though.

Yes, but it is usually baked in something else. If you Google "baked spinach recipes," you will see many recipes that use spinach in some way (casseroles, side dishes, and so on).