Heat oven to 350 degrees F. Lightly spray a 13-by-9-inch baking pan with cooking or baking spray.

In a large bowl, whisk flours, baking soda and salt to combine.

In a separate large bowl using an electric hand mixer or in the bowl of a stand mixer, cream butter and sugar on medium speed 2 minutes until light and fluffy. Reduce speed to low and stir in flour mixture until just combined. Stir in rolled oats.

Press half of mixture firmly and evenly into bottom of prepared pan. Bake 10 minutes to set.

Meanwhile, in a medium saucepan or skillet over medium-low heat, heat caramels and heavy cream. Stir constantly 5 to 7 minutes until mixture is fully melted and smooth. Remove from heat and allow to cool while dough is baking.

Scatter chocolate chips and chopped nuts evenly over par-baked dough. Pour caramel sauce evenly over the top (use a spatula if needed to spread the caramel sauce). Sprinkle evenly with remaining dough.

Bake 15 to 20 minutes until top is lightly browned and baked through. Cool completely on a cooling rack, then cover and chill at least 2 hours before cutting into bars.