Heat oven to 350°F. Grease bottom and sides of 15x10x1-inch pan with shortening or cooking spray.
In large bowl, mix flour, sugars, baking powder, baking soda and cinnamon. Add oil, applesauce, vanilla and eggs; beat with electric mixer on low speed until smooth. Spread in pan.
Bake 28 to 32 minutes or until toothpick inserted in center comes out clean and surface is deep golden brown. Cool completely, about 1 hour.
Frost with dulce de leche frosting. Cut into 6 rows by 4 rows, but leave in pan.
To decorate, spoon vanilla frosting into resealable food-storage plastic bag; seal bag and cut off 1 tiny corner. Pipe vanilla frosting in a spiral in corner where 4 squares meet (see diagram). Pull a toothpick from corner of each square through lines of frosting 4 to 5 times to create spiderweb. Repeat to make 6 webs.
Place 1 peanut butter candy and 1 baking bit next to spider web on each square. Spoon chocolate frosting into another resealable food-storage plastic bag; seal bag and cut off 1 tiny corner. Pipe chocolate frosting to make 6 legs for each spider.