Preheat oven to 350 degree F. In a medium mixing bowl, stir together flour, baking powder, cinnamon, baking soda, and salt; set aside. In a large mixing bowl, beat together sugar, pumpkin, eggs, and oil with an electric mixer on medium speed. Beat in the flour mixture until well mixed. If desired, stir in pecans.
Spread batter in an ungreased 15x10x1-inch baking pan. Bake for 20 to 25 minutes or until a wooden toothpick inserted in center comes out clean. Cool in pan on a wire rack. Prepare Cream Cheese Frosting; spread over top Cut into bars. Top with desired toppings. Store in the refrigerator. Makes 24 bars.
Cream Cheese Frosting
Allow cream cheese and butter to stand at room temperature for 30 minutes. In a large mixing bowl beat cream cheese, butter, and vanilla with an electric mixer on medium speed until light and fluffy. Gradually beat in powdered sugar to reach spreading consistency.