In a large mixing bowl, cream butter and brown sugar. Add eggs, one at a time, beating well after each addition. Beat in maple flavoring. Combine the flour, baking powder and salt; add to creamed mixture alternately with milk. Cover and refrigerate for 2 hours or until easy to handle.
On a lightly floured surface, roll the dough into a 18-in. rectangle. Brush with melted butter to within 1/2 in of edges. Sprinkle with pecans. Fold one short side of dough a third of the way over filling; fold the other short side over the top, forming an 18-in. x 3-in. rectangle. Cut into 3/4 in. strips; twist each strip twice.
Place 2 in. apart on ungreased baking sheets. Bake at 350 degrees F for 20-22 minutes or until golden brown. Remove to wire racks to cool. In a small bowl, combine icing ingredients until smooth. Drizzle over twists.