I've been a self-taught cake decorator for almost 20 years now (wow, that's intense to say, considering I'm only 38, lol). anyhoo.....I'd seen at the little boutiques the faux cakes, cupcakes, candies and such sitting around the vignettes of tea sets and tea cups and thought, 'man, I could do that, I can just make my own.' So got on a tangent and done some 'studyin' up' on the subject...research (blah, I LOATHE research, lol) but I did it...and because these types of crafters and decorators keep the product secrets closely guarded, it was only through trial and error that I found the correct products and techniques to make them and to make them look good. And since I HATE it when people don't share those secrets, thinking, 'if I don't share, then that's more people that will PAY for the stuff that I make.'....ya'll, there's a time and place for that thinking, making faux cupcakes, in my opinion, is not where that belongs, lol. So, I'll tell you MY findings and what I used. Other's do other things, probably, dunno cuz they don't share what they use, lol...but this is what I found.
First, you're gonna need spackling. For the light fluffy decorations such as leaves, star piping with the large star tips, and such, I found that they turned out so much better when I used the Fast'N Final Lightweight Spackling. To 'ice' the cakes and cupcakes, I didn't want to 'waste' the lightweight (I did on some though) so I used regular Vinyl Spackling. For decorations, I used silk flowers, but others have used paper flowers. If you're good and quick, you can use the Lightweight Spackling (the vinyl will be too heavy) to pipe flowers and roses, but you have to remember how time consuming that can be, and if it's to SELL rather for your own decor, people may not want to pay for the labor and time that it takes...just something to keep in mind.
Other supplies needed, disposable cake decorating bags, tip couplers, and whatever tips you want to use, as well as whatever color acrylic paints that you want. If you want to add candy sprinkles, look around for 'just the right' look of seed beads, use your imagination to get the look that you want. I also took various colored foam sheets and a reg. hole punch, punched a bunch out and used them as the round candy sprinks you see on all the full and yummy cupcakes. For cupcakes, this is a big time trial and error...you will definitely need a cheapy or old cupcake pan (or 2), cupcake cups of your choice and spray foam. You need to keep in mind that they will need to be weighted down so that they don't just roll around or easily toppled when being used for decor...I've found that using the glass pebbles at Dollar Tree works well...and also, don't get the super cheap, flimsy liners, because the foam will expand them and you won't be able to use them, they'll turnout ugly looking. You might want to cut out a lightweight cardboard disc to fit in the bottom of the cupcake because the underside of the liner will 'pucker' and look unsightly after the foam dries. Once you start using the spray foam, you'll usually have to use it all, it doesn't really 'keep' well...so I usually have several prepared cupcake pans lined up at once, and you'll have plenty of cupcakes practice on and make for yourself, gifts, craft shows and such. Place the liner in the cupcake pan, place the cardboard disc in the bottom, put a couple of the glass pebbles down...prepare the rest the same way. Next, begin to spray the cupcakes. When I start spraying, I like to spray slooooooooooooowly, in a circular motion around the pepples, then over the pebbles, then I place the nozzle inside the pile and continue to slowly spray until you have a mound that barely reaches the top of the liner. Don't worry, it will expand upward to make a mound over the top. By putting the nozzle inside the mound, it promotes a rounded, smooth cupcake surface, and looks like a real cupcake. If you keep the nozzle above the mound and spray, it'll work, as well, however you'll end up with bumps and ridges and it won't look natural at all. After a few hours, you'll be tempted to think that the cupcakes are done and will be able to be painted...nope!!! if you do that, then the next morning you'll look at them and find that they were still expanding and you'll be able to see a considerable amount of unpainted foam. Just wait until the next day to paint them (which is optional). If you choose to paint your cupcake tops, which I like to do, you'll want to mix a couple of paints to get the right color. I find that buttercream yellow with just a couple of drops of caramel brown, dabbed on with a foam brush, makes them look like a vanilla cake and really yummy. A little paint will go a long way, because you'll be decorating the tops, you'll usually only be able to see a little of the edges, so just paint about 1/2" from the liner up. OH, pixie dust!! I LOVE pixie dust!!! It's a super fine glitter that makes my faux cakes 'glisten' and I just love the look it gives...you can see it sparkle in the photo.
Now, for cakes and cookies, (petite fours and little tarts are totally different animal...will explain later in the post), you'll use styrofoam, either already formed or that you'll cut yourself, it's your choice. For the larger cakes, I use the regular foam (not the kind of foam you can add water to, never use that kind of foam for these projects) blocks or discs. The discs, I'll add 'icing' between them to make them taller, then you 'ice' the outside and top (hint, I use a lazy-susan plate when I decorate my cakes and such, but to 'ice' them all over, I like to take a two pronged fork, and stick the fork in the bottom, that way I can get all of the cake covered.
Your 'icing'....I like to use the vinyl spackling for all-over icing, because it'll keep your cost down and it'll make your lightweight spackling last longer. Add a few squirts of whatever acryllic paint that you wish and stir. The is a perfect use for those butter bowls you've been keeping around, lol. Use a cake spatula to 'ice' your cakes and cupcakes.
You can also make foam 'faux' cookies by either cutting foam to your liking (which is messy) or by buying the styrofoam shapes at your craft store. You can use Fimo clay to make other embellishments, such as chocolate chips, super easy, and look SO realistic!
Ok, I think that's about it...I've uploaded one photo here, but I've posted many more in my 'photo gallery' for everyone to see.
Petite fours and little tarts aren't made by using styrofoam, they're made by using newspaper, water, and glue. Martha Stewart has an excellent tutorial on those, which is the one that I used when I made mine.