1. In large bowl with mixer at medium speed, beat peanut butter, margarine, brown sugar, corn syrup and eggs until smooth. Reduce speed; beat in 2 cups flour, baking powder, cinnamon and salt. With spoon, stir in remaining 2 cups flour. Wrap dough in plastic wrap; refrigerate 2 hours.
2. Preheat oven to 325°F. Divide dough in half; set aside half.
3. On floured surface roll out half the dough to 1/8-inch thickness. Cut with floured bear cookie cutter. Repeat with remaining dough.
4. Use scraps of dough to make bear faces. Make one small ball of dough for muzzle. Form 3 smaller balls of dough and press gently to create eyes and nose.
5. Bake bears on ungreased cookie sheets 10 minutes or until lightly browned. Remove from cookie sheets; cool completely on wire rack. Decorate as desired using frosting to create paws, ears and bow ties.