Preheat the oven to 350°F. Cover a 13" x 9" pan in non-stick foil and spray with canola oil (for easy removal). Set aside.
In a bowl, whisk the olive oil, eggs, coffee, sugar, and vanilla extract together. Add the flour and baking powder and stir together.
In a microwavable bowl, melt the chocolate chips (stirring every 30 seconds until melted). Add the melted chocolate to the mixture and stir until well combined. Pour into the pan and bake for about 20 minutes, until done.
Place the marshmallows evenly on top of the brownies. Bake until the marshmallows are melty, 5-10 minutes.
Meanwhile, in a medium sauce pan over low heat, combine the chocolate chips, peanut butter, and butter. Stir frequently. Once everything has melted, remove from the heat and stir in the cereal. Spoon over the brownies and marshmallows. Swirl into the marshmallows.
Let chill in the fridge until set, about 45 minutes. Cut into bars and enjoy!