Chocolatey Chunk Caramelitas

Meet caramelitas ... introduce yourself ... get friendly, because soon you will be very good friends.  They're so simple--a layer of buttery, flaky oat shortbread, topped with dark chocolate chips and fleur de sel caramel, and then another layer of the oat shortbread.  But then it all bakes together, and the caramel melts down over the chocolate, into the shortbread.  The oats start to toast and take on a nutty flavor.  And then they're done, and all you have do is wait for them to cool.  They do need to be completely cool before you slice them, not just kinda, or they'll crumble all over the place.  A short stay in the fridge does wonders if you're impatient.  I found the original recipe over here, but I'm posting my few changes below.

Caramelitas

5-6 oz fleur de sel caramel sauce (I used a jar I had on hand, but you can also make it yourself)
3/4 c unsalted butter, melted
3/4 c brown sugar
1 c flour
1 c old-fashioned oats (not instant)
1 tsp baking soda
1 c semisweet chocolate chunks (I used Callebaut)

Combine the butter, brown sugar, flour, oats, and baking soda in a bowl.  It will be crumbly.  Pour half of the mixture into a foil-lined 8x8 (or similar) baking pan.  Bake for 10 min. at 350 degrees.  Then sprinkle the chocolate over the base layer and the caramel over that.  Crumble the remaining oat mixture on top, and bake for 20 min., or til golden brown. Let cool completely before slicing.  These freeze very well -- I wrapped the rest of mine individually, so I can pull one out of the freezer, without being tempted by the entire pan.