I got this recipe at a cookie exchange. (Thanks, SL!) It makes rich, sweet, pretty layered bars that are always a hit. They also keep well, so they are nice for making ahead.
Preheat oven to 350 degrees. Spray a 9x13 pan with cooking spray.
In a mixer bowl, combine first 6 ingredients (2 cups flour, oats, brown sugar, butter, baking soda, and salt).
Dump half of the oat/flour mixture into the prepared pan. Press to create a bottom crust with no holes. If needed, use a bit more than half the mixture to make sure the pan is well covered.
Bake bottom crust at 350 degrees for 10 minutes.
Mix the remaining 6 Tbsp. flour into the caramel ice cream topping. Stir until evenly combined. Chop nuts.
When the partially baked crust comes out of the oven, sprinkle evenly with chocolate chips. Then sprinkle nuts on top. Pour caramel/flour mixture evenly over that. Finally, crumble the remaining flour/oat mixture on top to form a final layer.
Return pan to the hot oven and bake an additional 30-40 minutes. The caramel should be hot and bubbly and the oatmeal topping lightly brown.
Allow bars to cool thoroughly before cutting. Sometimes the edges are hard to get off of the pan, but you can pick them off for nibbling after you have cut the rest of the bars out of the middle! Store in the refrigerator for best results.