Self-hardening pottery clay Waxed paper Cardboard Scissors Nature objects Butter knife Matte acrylic varnish Paintbrush White tempera paint Sponge
Create a template by cutting a 4-inch square out of cardboard. Cover the work area with a piece of waxed paper and use a rolling pin to flatten a 2 1/2-inch ball of clay to 1/4-inch thickness for each coaster
Arrange a pattern of leaves or pine needles atop the clay and gently press them into the clay with the rolling pin, leaving distinct but shallow impressions. Make pine cone images by gently pressing in the cones by hand.
Remove the foliage and place the cardboard template on top of the clay. Use a butter knife to cut around the cardboard, and then lift away the excess clay.
Place the coasters on a clean piece of waxed paper and set aside to dry according to the package directions; this can take a day or so.
Once the coasters have dried completely, cover with a thin layer of matte acrylic varnish. Let dry for 45 minutes, then accent the designs using a damp sponge to apply a light layer of white paint to the raised area of the coaster and dab a little more into the impressions to highlight them. Let the paint dry thoroughly before adding a last coat of varnish.