Preheat the
oven to 350°F/180°C/gas 4. Butter two cookie
sheets.
Sift the
flour, cocoa, baking powder, nutmeg, and salt
into a medium bowl.
Beat the
butter and sugar in a large bowl with an
electric mixer at high speed until creamy.
Add the egg
yolk, beating until just blended. Mix in the dry
ingredients. Drop teaspoons of the dough 1 inch
(2.5 cm) apart onto the prepared cookie sheets.
Bake for
12-15 minutes, or until firm around the edges.
Transfer to racks to cool.