These bars take no time to make and they are super delicious. It’s like taking a bite into summer!
Preheat oven to 350 degrees Fahrenheit. Grease a 9- x 13-inch baking pan.
In a large bowl, combine oil, egg, vanilla, graham cracker crumbs, sugar, flour, baking powder, salt, and cinnamon.
Press half of the batter into the prepared pan. Bake for 13 minutes.
Break the chocolate into squares and place evenly on top of crust. Top evenly with marshmallows. Crumble remaining batter over chocolate and marshmallows.
Bake for an additional 13 minutes. Let cool for 10 minutes before cutting into squares.