Here's a fairly simple version of an acorn decorated cookie just in time for autumn.

My favorite acorn cookie cutter is found here.

Using dry caramel dust, brush it over the bottom portion of the acorn cookie.
(see photo & video below)

Outline and flood the topper on the acorn with a dark brown glaze.

Allow the glaze to dry for about 2 hours.

Using a fondant tool, press in the arcs across the topper on the acorn.
(see photo and video below)

SImple and recognizable........just like we want 'em. :)