Grandma Pat'S Caramel-Fudge Brownies

Preheat oven to 350 degrees.
Grease a 13 X 9-inch cake pan with Pam.
In a medium-sized bowl, using an electric mixer, mix together caramel topping (heating remains of jar, partially covered in plastic wrap, 20-25 seconds in microwave to extract all topping), 1/4 cup flour, and 1/3 cup of the evaporated milk.
In a larger bowl, using an electric mixer, beat cake mix (+ 3 tablespoons flour, high altitude only), remaining 1/3 cup evaporated milk mixed with chocolate extract (optional), and melted butter until well mixed...about 1 minute. Mix in walnuts with a wooden spoon.
Flatten surface and divide cake mix in half with a spatula. Press half of it into bottom of prepared pan. (It's easy to handle, not sticky). Bake 15 minutes (about 18 minutes high altitude) or until set.
Remove from oven and pour caramel mixture over baked layer. Sprinkle evenly with chocolate chips. Evenly distribute remaining cake mixture in small chunks over the top.
Return to oven and bake 30 minutes (about 32 minutes high altitude) or until top is crusty. Cool to room temperature and cut into squares using a sharp or serrated knife. Chill.
NOTE: Immediately after baking, brownies will look underdone and gooey. They will FIRM UP to a nice consistency after they are refrigerated. To chill quickly, place in freezer for awhile.
Cover and refrigerate up to 1 week, or freeze. They're still soft and pliable right out of the freezer. Always serve chilled.