In a large bowl, cream together butter and brown sugar. Beat in egg, vanilla and maple flavoring. Beat in salt and flour until a smooth dough is formed. Shape dough into a log 12 inches long, wrap in wax paper, and refrigerate overnight.
Preheat oven to 350 degrees F (180 degrees C). Line cookie sheet with parchment paper.
Slice dough into 1/4 inch slices. Place slices on cookie sheet. Top each cookie with a pecan half. Bake for 10 minutes in preheated oven, or until golden brown.