'ei' or 'ij'

an egg or an ice cream?

Another confusing beauty in the Dutch language: do I write 'ei' or 'ij'?

Both sound exactly the same, but it is extremely important to use the correct written form in order to avoid confusion. There are no 'rules' or 'mnemonics' for it, you will just have to study it, word for word. Undust does dictionaries and unfold those bookworm-glasses!