Add flour, oats, baking soda and salt. Keep aside 1 cup. Press the rest into a lightly greased 9x13” pan.
Cover with marshmallows and chocolate chips. Sprinkle with remaining oat mixture. Bake at 325 degrees for 18 to 20 minutes.
Let cool on rack - it is easiest to cut them while they are still slightly warm. Serve warm with a fork or let cool completely to serve as pretty squares :)
Recipe by Hidden Ponies at https://hiddenponies.com/2012/06/saturday-sweets-smores-oat-bars/