In a 9×9 inch baking pan, spray with non-stick cooking spray. Set aside.
In a large non-stick pot over medium heat, melt butter. Add in marshmallows and stir together with butter until marshmallows have melted and become creamy.
Stir in vanilla extract.
Fold in grahams cereal until all marshmallows and grahams are evenly mixed together. Mix in 1 cup of chocolate chips. Spread treats into sprayed baking pan.
Press into pan and sprinkle remaining 1/4 cup of chocolate chips on top of the treats, lightly press into top of treats to make sure they stick.