Prepare the cake as advised in basic instructions baking in at least a 9"x12" baking pan. Preferably, a pan 12"x17" would be used. When the cake is done, let cool slightly and then remove from pan. Place on a wire rack to cool. When substantially cool, use a long knife with serrations, to even the top surface.
Place the entire cake, bottom side down, on a large cookie sheet or other metal pan that is flat. You may turn a large type of baking pan over and use the bottom of the pan, but be sure to secure the pan from slipping. Once the cake is leveled, set aside.
Take two tablespoons of the shortening and one tablespoon of the butter and soften together with about 1/2 pound of the 10X sugar. When well softened together, add a few drops of water, then add a second 1/2 pound of the 10X with a little more water. Beat at a medium to high speed for several minutes to get to an icing consistency.
Then, remove the mixer, and take about one cup of the icing and set the rest aside with a damp paper towel as a cover. Add water to the cup of icing, and stir by hand until the icing is like soup. Then, stir solidly. Using a flat spatula, spread the icing over the top of the cake and cover the sides. You are sealing the crumbs to the cake, and making a cutting surface.
Next, start your first cut. Using a small, flat sharp spatula, (decorator’s spatula). Cut a one inch slice of cake sideways. Move the slice slightly away from the whole cake and use the spatula to seal the cut edges of both the cutting and the freshly cut side of the whole cake. Next, size up the slice of cake that you have. It should be about one inch wide, and should be the width of the cake in length. Using your small, sharp spatula, Start cutting one inch at a time, which will give you one inch squares. As you cut, seal each side of the petit fours with the soupy icing.
Add more icing to the soupy mixture, and keep adding water and stirring as you go. Do not make a vast quantity of this mixture to begin with. You will end up throwing it away. Do not worry that crumbs get into this mixture. That is what it is for. However, do not attempt to recover this mixture into future icing.
Next, let each petit four set. As you cut the one inch squares, set each square on a metal rack, preferably with a cookie sheet or some kind of flat pan to set inside. You need a sheet of pan of some sort to catch the glaze that is the next step. It is important to let the petit fours set for several hours at this stage, before applying the glaze. If you apply the glaze too soon, you will simply melt the icing that you have just applied and you will have a gooey glob instead of a lovely little cake. So, be patient. Set the cakes aside and clean up in preparation for the next step.
When the cakes are set to the touch, and no icing sticks to a clean finger lightly tapping the top of one cake, you are ready to make the glaze. Glaze cannot be made in advance and should not be made in vast quantity. Start with approximately one pound of 10X sugar. MICROWAVE about 3/4 of one cup of water in a measuring cup with a sturdy pouring apparatus. Do not attempt to do this out of an ordinary cup. You need to have the pouring spout to make sure that you can pour directly and carefully a small amount of water at a time. Microwave the water on high for about a minute. Then, very gently, with either a hand mixer or a whisk, add the hot water and stir until you have a kind of a paste. Do not add anything else to this glaze. When you have a soft paste formed, add a few more drops of water, sir a little bit more for smoothness and then microwave the mixture you have just made for no more than 45 seconds on high. Remove the glaze mixture from the microwave immediately. Stir gently, to smooth the mixture. This is very important. Take time to make sure that you stir carefully and do this part by hand so as not to add air bubbles to the glaze.
Then, bring your glaze mixture close to your rack holding your set petit fours. Using a small spoon, spoon the glaze over the petit fours, making sure that all four corners of the petit four are covered. Do not attempt to recover the glaze that is poured onto the catch pan below. Simply continue to make more glaze until you are completed. If you have good coverage, your petit fours are ready, and should be ready to be decorated in a few hours. If you are uncertain, then let set for a few hours and then repeat the glazing process and let set for at least 8 hours before decorating.
Decorate with buttercream or royal icing in your preferred design. When you are ready to remove the petit fours from their pans, use the same sharp small spatula that you used before, and slide the edge of the spatula under the petit four to remove each cake from the rack. Place in a 1" candy/petit four cup, and box or place upon a tray to serve. If kept in a cool dry environment,