These Smores Bars are best when completely cooled. Put them in the refrigerator to cool completely. I find it best to refrigerate them overnight then slicing. They will soften again when they come to room temperature. They’re still good while warm, although difficult to eat because the chocolate and marshmallow will be soft and gooey.You can slice these into 16 bars or 12 larger bars.
Spray or grease an 8x8 baking dish. For ease of slicing, line the pan with parchment with a little overhang.
Whisk together butter and brown sugar until combined. Whisk in the egg, salt, and vanilla.
Stir in the flour and crumbs and mix until combined.
Press ⅔ of the dough evenly into the pan.
Sprinkle the top evenly with the chocolate chips.
Spray or grease a 2 cup measure with baking spray and measure the Fluff. If using a 7 ounce jar of creme, transfer the whole thing into the measuring cup. For ease of spreading, microwave the fluff for 15 to 30 seconds. Now you can easily spread the fluff over the chocolate. It should come out of the measuring cup easily because it was greased.
Sprinkle the mini marshmallows evenly over the creme. Break off pieces of the remaining dough and scatter it evenly over the marshmallows.
Bake for 25 - 30 minutes. Start checking after 23 minutes.
Let cool, then refrigerate until firm - at least 4 hours - or it will be very messy and soft. Slice and enjoy.
For a cleaner slice, wipe down your knife between each slice to remove the sticky fluff.