I would like to make petit fours for the first time. The ones I really like are square pieces of cake without any layers or filling. I would like to know of the type and size of pan they should be made in since they aren't going to be in layers and also how to make them into squares? Are cookie cutters used? If so what size? I am trying to figure out if sponge or pound cake would be best to make so they are nice and moist sponge or pound cake. Also what kind of frosting, tip type and size are used to decorate the top. Please simplify this process if possible. Thanks.