I bought a book from Chatsworth shop on how to make them but I found it too complicated. Yesterday I came across this website:
It explains simply how to make them. I tried this recipe yesterday rather than the book from Chatsworth at it proved more successful than my last attempt. I keep over whipping the egg whites and when I add my food dye it separates and looks curdled. The instructions for any macaroon recipe say to leave the egg whites separated for 24 hours before using so I am going to try making them again doing this. I separated my eggs last night... The attempt yesterday ended up cracked, overcooked and and well, just not macaroon quality!