For the bun, roll conditioned beige clay between your palms into a log about 3⁄8 in. (1 cm) long and 3⁄16 in. (5 mm) wide. Press gently so that the shape does not distort.
Use a blade to cut down the length of the bun, but do not cut all the way through.
Use sandpaper to grate brown chalk pastel into a powder. Use a stiff brush to stipple the bun with the powder so that it is tinted and slightly dimpled, creating a baked effect.
Roll a thin log of conditioned burgundy clay, about 3/8 in. (1 cm) long and 1/8 in. (3 mm) wide. Curl up the ends of the shape by pressing it gently between your fingers.
Place the hot dog in the bun and use black permanent marker to draw grill lines onto it. Carefully prick each end of the hot dog with a toothpick to make a small indent.
Roll a long, thin snake of conditioned yellow clay for the mustard, about 3/4 in. (2 cm) long and 1⁄32 in. (1 mm) wide. Zigzag the mustard clay back and forth over the hot dog, using the toothpick to make minor adjustments to the positioning, since the clay is easier to control this way.
Continue zigzagging the mustard on until the whole hot dog is covered.
Use the toothpick to insert an eyepin under the hot dog and apply a little translucent liquid clay so that it stays in place. Bake the clay, following the manufacturer’s instructions.