Preheat oven to 350 degrees F.
Spray 9x13" baking pan with cooking spray and set aside.
In large bowl, combine melted butter and brown sugar.
Beat with electric mixer with paddle attachment until well combined, about 1 minute.
Add eggs, one at a time, mixing until combined.
In medium bowl, combine flour, baking soda, salt, and cinnamon, stirring to combine.
Add to butter mixture in large bowl, mixing to combine.
With a spatula, fold in chopped apples and Snickers.
Pour into prepared pan, spreading out evenly with spatula.
Bake in preheated oven for 27-32 minutes, until golden brown.
Let cool completely.
Cut into squares and enjoy!