a baseball glove-shaped cookie cutter (about 4 inches wide), a #2 or 3 pastry tip and a small pastry bag
Butter a 9-by-13-inch baking pan, line the bottom with parchment paper and butter the parchment.
Put the marshmallows and butter in a large pot and warm over medium heat, stirring, until completely melted. Add the rice cereal and stir until completely coated. Pour the mixture into the prepared baking pan. Lightly oil your hands or a little square of plastic wrap and press and smooth the cereal evenly into the dish. Cool until set, but not totally dry, about 30 minutes.
Lightly oil a sheet of parchment paper and turn the block of crispy treats out onto it. Oil a baseball glove-shaped cookie cutter (about 4 inches wide) and cut out 6 baseball gloves, oiling the cookie cutter between each. Gather some of the scraps and make 6 baseballs, about 1 1/2 inches in diameter.
Put the candy melts in a small bowl and melt them in the microwave in 30-second intervals at 30-percent power until thoroughly melted and smooth. Add the shortening (or paramount crystals) a little bit at a time until slightly thinned to a nice coating consistency.
Coat the balls in the candy melts and let stand until completely set, about 20 minutes.
Fit a #2 or 3 pastry tip into a small pastry bag and fill the bag with the red decorating icing. Pipe a red line in an elongated semicircle shape similar to the lines of a baseball onto each ball. Then pipe small, crosswise lines along the semicircle to represent the stitching on a baseball.
Dab a little of the candy melt on the bottom of the balls, then press them lightly into the center of the gloves. Let stand until dry and set.