Prepare a 9x13 dish by spraying with oil, then line it with parchment paper. Spray the paper lightly and set the pan aside for later.
Place the butter in a large pot and melt over a medium- low heat. Once melted, bump the heat up to medium and cook, stirring regularly, until the butter begins to turn a light amber.
Remove the pot from the heat and stir in the marshmallows. Once the marshmallows are starting to melt and incorporate into the butter, place the pot back on a low heat. Stir until the mixture is completely melted and combined.
Remove from the heat and stir in the maple syrup, vanilla, cinnamon, and salt. Once well combined, scrape any excess mixture off of the spatula and spray the spatula with oil. Fold in the puffed rice cereal and cinnamon sweet bits until completely combined.
Dump the mixture into the prepared pan and press gently into an even layer. Sprinkle with a few more cinnamon sweet bits and use a greased spatula to gently, but firmly, press it into the pan. I like to finish it off by greasing the bottom of a glass and gently pressing the surface to ensure it is well packed and even.
Let the rice krispie treats cool and set up for at least 30 minutes, or overnight. Once firm, slice into squares.
To store: layer the squares between parchment paper in an airtight container. Keep on the counter for up to a week.