Lightly spray a 9x13 inch pan. Set aside.
In a large pot over low heat, melt the butter. Add the marshmallows and stir gently until just melted and smooth.
Remove from heat and stir in vanilla and salt.
Add the Cocoa Loops and fold until everything is evenly coated.
Transfer the mixture to the prepared pan. Use lightly buttered or damp hands to gently press the treats into an even layer. Don’t compact them or the bars will turn dense.
Let the treats cool at room temperature for 1 hour before slicing into squares.