Add the cake mix, oil, eggs, and 1/2 the cinnamon to a mixing bowl and mix together until evenly combined.
1 15.25 oz box yellow cake mix, 1/3 cup canola oil, 2 large eggs, 1 tbsp ground cinnamon
Spray an 11x7" brownie pan with non stick cooking spray, or line it with parchment paper, then transfer the batter to it. Spray a spatula with non stick cooking spray, then use it to spread the batter out in an even layer.
Add the sugar and remaining cinnamon to a small bowl, and stir together until evenly combined. Spread this mixture evenly out overtop of the batter, and gently press in with the back of a spoon to help it stick.
1/4 cup granulated sugar
Bake at 350° for 15-17 minutes, just until set and the edges have puffed up slightly.
Carefully remove the hot pan from the oven and let cool for 5 minutes.
Slice into 12 even bars, serve, and enjoy!