Preheat your oven to 350°F and lightly spray a baking sheet with cooking spray. While the oven heats, measure out all your ingredients and have them ready—this takes just a minute and keeps you organized. In a small bowl, combine the sugar and ground cinnamon, stirring until well mixed and set aside. I like to use freshly ground cinnamon here because it has so much more aromatic punch than pre-ground, and it really makes these cookies shine.

In a medium bowl, combine the vanilla cake mix, softened butter, eggs, and vanilla extract. Stir everything together until you have a cohesive dough—it will be thick and slightly sticky, which is exactly what you want. Don't overmix; just combine until no streaks of dry cake mix remain. The butter should be at room temperature so it incorporates smoothly and creates a tender cookie texture.

Using a cookie scoop or spoon, portion the dough from Step 2 into small balls about the size of walnuts, and place them on a plate. Working with a few at a time, roll each dough ball in the cinnamon-sugar mixture from Step 1, coating all sides generously. I find it helpful to work quickly so the cinnamon-sugar sticks to the slightly sticky dough—if your hands get too messy, just wipe them on a damp towel and continue.

Arrange the coated dough balls on your prepared baking sheet, spacing them about 2 inches apart—they'll spread slightly as they bake. Place the sheet in your preheated 350°F oven and bake for 9 to 11 minutes, until the edges are set but the centers still look slightly underdone and soft. The cookies will continue to cook on the hot pan after you remove them, so pull them out when they look just barely done—this keeps them chewy inside.

Let the cookies cool on the baking sheet for 2 to 3 minutes—they'll firm up just enough to move without breaking. Transfer them to a wire cooling rack to finish cooling completely, which ensures they set properly without becoming hard and brittle. This brief cooling on the pan followed by the rack gives you cookies with the perfect texture: crispy edges and a soft, chewy center.