Preheat the oven to 350 and grease a 9x13 baking pan.
In the bowl of an electric mixer, cream together butter and sugars for a couple of minutes on medium-high speed.
Add eggs, one at a time, beating after each addition. Add vanilla and beat until mixed. Scrape sides and bottom of the bowl. Mix until all incorporated.
Turn off mixer and sift in flour, baking soda, baking powder and salt. Mix ingredients on low speed until just combined. Scrape sides and bottom of the bowl and mix a couple more times.
Fold in 1 cup of caramel bits and 1 cup of marshmallows into the batter.
Spread cookie batter in the baking dish, evenly.
Bake for 20-23 minutes.
Take out and spread remaining marshmallows and caramel bits over the top.
Place back into the oven and turn on the broiler until the marshmallows are melted and toasted on top. Watch it carefully because marshmallows can burn very fast. It will take somewhere between 45 seconds and a minute and a half, depending on your broiler.
Recipe from Lyuba @ willcookforsmiles.com All images and content are copyright protected. Please do not use my images without prior permission. If you want to share this recipe, please simply link back to this post for the recipe. Thank you.