Chewy Pumpkin Caramel Bars

2 2/3 cups all-purpose flour
2 2/3 cups granulated sugar
2 1/2 teaspoons ground cinnamon
2 1/2 teaspoons baking powder
1 1/4 teaspoons baking soda
1/2 teaspoon salt
1 cup solid pack canned pumpkin
3/4 cup vegetable oil
27 caramels, unwrapped (about 9 ounces)
1/4 cup evaporated milk
1/2 cup chopped nuts, divided

Combine flour, sugar, cinnamon, baking powder, baking soda and salt in large mixer bowl. Add pumpkin and oil; beat until blended (batter will be thick). Spread two-thirds batter into greased 13 x 9-inch baking pan. Bake at 375 degrees F for 20 minutes.

Combine caramels and evaporated milk in small saucepan; stir over low heat until caramels are melted. Pour caramel mixture over baked layer; sprinkle with 1/4 cup nuts. Drop remaining batter by heaping teaspoons over caramel mixture; sprinkle with remaining nuts. Return to oven for 20 to 25 minutes (top layer will be slightly soft). Remove to wire rack to cool completely.