Preheat the oven to 350 degrees F.
Place the nuts and corn syrup in a 2-quart heavy-bottomed saucepan and place over low heat to liquify the corn syrup. Heat the mixture until the corn syrup is thin enough to coat the nuts evenly, 3 to 4 minutes.
Remove the saucepan from the heat. Using a large slotted spoon, allow the excess corn syrup to drain as you scoop the coated nuts onto a parchment paper-covered baking sheet. Be sure to spread them in an even layer so they will roast evenly in the oven.
Bake until they are evenly caramelized, 15 to 20 minutes. To test for doneness, you can also break a nut in half and check to see if it is light brown on the inside. Keep an eye on the nuts because the sugar will burn very soon after it caramelizes. Remove the baking sheet from the oven and place on a wire rack. When the nuts are completely cooled, break apart any that are clustered together.
Fill a cornet halfway with bittersweet chocolate. Pipe a chocolate circle 1 1/2 inches in diameter onto a parchment paper-covered baking sheet. If you do not have a cornet, you can use a spoon; drop a spoonful of the chocolate onto the parchment paper and spread it into a 1 1/2-inch diameter circle with the back of the spoon. In either case, keep the thickness of the circle as even as possible. Make about 10 circles, then create your own design as you top each circle with the cocoa nibs, roasted nuts, and candied fruit. Work quickly, or the chocolate will set before you've accomplished this. If the nuts and fruit do not stick to the chocolate, lightly dip them in the bowl of tempered chocolate and "glue" them to the top of the disk. Repeat the process until you have used all of the bittersweet chocolate, nuts, and candied fruit.
Set the Mendiants aside to harden until ready to serve. Serve side by side rather than in a pile. Store the Mendiants in an airtight container at room temperature for up to one week.
How to Temper Chocolate(From Dessert Circus, Extraordinary Desserts You Can Make At Home by Jacques Torres):
Chocolate is tempered so that after it has been melted, it retains its gloss and hardens again without becoming chalky and white (that happens when the molecules of fat separate and form on top of the chocolate). There are a variety of ways to temper.
One of the easiest ways to temper chocolate is to chop it into small pieces and then place it in the microwave for 30 seconds at a time on high power until most of the chocolate is melted. Be very careful not to overheat it. (The temperature of dark chocolate should be between 88 and 90 degrees F, slightly warmer than your bottom lip. It will retain its shape even when mostly melted. White and milk chocolates melt at a temperature approximately 2 degrees F less because of the amount of lactose they contain.) Any remaining lumps will melt in the chocolate's residual heat. Use an immersion blender or whisk to break up the lumps. Usually, chocolate begins to set, or crystallize, along the side of the bowl. As it sets, mix those crystals into the melted chocolate to temper it. A glass bowl retains heat well and keeps the chocolate tempered longer.
Another way to temper chocolate is called seeding. In this method, add small pieces of unmelted chocolate to melted chocolate. The amount of unmelted chocolate to be added depends on the temperature of the melted chocolate, but is usually 1/4 of the total amount. It is easiest to use an immersion blender for this, or a whisk.
The classic way to temper chocolate is called tabliering. Two thirds of the melted chocolate is poured onto a marble or another cold work surface. The chocolate is spread out and worked with a spatula until its temperature is approximately 81 degrees F. At this stage, it is thick and begins to set. This tempered chocolate is then added to the remaining non-tempered chocolate and mixed thoroughly until the mass has a completely uniform temperature. If the temperature is still too high, part of the chocolate is worked further on the cold surface until the correct temperature is reached. This is a lot of work, requires a lot of room, and makes a big mess.
A simple method of checking tempering, is to apply a small quantity of chocolate to a piece of paper or to the point of a knife. If the chocolate has been correctly tempered, it will harden evenly and show a good gloss within a few minutes.
How to Make a Cornet(From Dessert Circus, Extraordinary Desserts You Can Make At Home by Jacques Torres):
The Cornet: A cornet is a small piping bag made from parchment paper. It is usually used to make fine decorations.
Cut an 8 by 12 by 14 1/2-inch triangle from a sheet of parchment paper. Hold the middle of the long side of the triangle between two fingers of one hand. Take the tip of the triangle on the short, wide end and roll it toward the other tip of that same end while simultaneously pulling it in an upward motion. The tip of a cone will form where your thumb and finger hold it on the long side.
Release your grip from the long side, so that you are now holding the two corners where they meet. The paper will already resemble a partially formed cone. Roll the remaining tail until it is completely rolled into a cone. There will be one point sticking up from the open end. Fold it inside toward the center, and crease the fold. Now you should have a cornet. To close the cornet once it has been filled, fold it away from the seam; this will keep the seam from opening. Use a pair of scissors or a sharp paring knife to cut an opening at the tip of the cornet to the desired size.