All right people let the Aussie tell you how it is done
Get the whitest, fluffiest, squarest, shop bought bread you can lay your hands one. It's got to be the supermarket, mass produced stuff, no bakery bread here.
Slather it with margarine or if you must spreadable butter. Never real butter.
Pour on as many hundreds and thousands as you can get to stick. I do this in a baking tray to catch all the ones that fall off. Hundreads and thousands are the multi-coloured ball shaped sprinkles. These are the only permittable sprinkles to be used
Cut into triangles and make sure the kids get some before the adults devour them all.
I made 2 loaves worth for DD"s 1st birthday. DH didn't think we needed it but it was the most popular food at the party!