I think they are adorable. I like them 5 layers tall (3 1/4-inch layers of cake and 2 thin layers of buttercream or ganache), but you could easily increase the layers if you like. I bake a standard “double layer” cake recipe in an 11x15 pan, remove cake from pan and chill it I torte it into layers using a cake saw (chilled cake is easier to cut, and I think it makes fewer crumbs too). Next, fill the layers with buttercream or ganache and chill until firm before cutting into the desired shapes/sizes. I find squares, rectangles, and diamonds very easy to cut using a sharp knife and ruler. Petit fours made from chocolate cake benefit from a thin layer of buttercream on all sides to prevent their dark color from showing through the poured fondant. Place the petit fours on a cooling rack suspended over a sheet pan before pouring the fondant on top. A fan gently blowing over the little cakes will speed along the drying process. If you plan far enough ahead, you can decorate with simple drop flowers made from royal icing. If you’re short on time, a simple diagonal drizzle of lightly tinted royal icing works well (pink for raspberry buttercream filling, brown for ganache, etc).