Step 1: Preheat the Oven and Prepare the Baking Pan

Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking pan with butter or non-stick spray, or line it with parchment paper for easy removal. This prevents the blondies from sticking and makes cleanup easier.

Step 2: Make the Blondie Batter

In a large mixing bowl, whisk together the melted butter and brown sugar until smooth. The butter should be melted but not hot, as overheating can cook the eggs when they are added.

Add the eggs one at a time, whisking well after each addition. Stir in the vanilla extract to enhance the overall flavor.

In a separate bowl, whisk together the flour, baking powder, salt, and cinnamon. Gradually add the dry ingredients to the wet ingredients, stirring with a spatula or wooden spoon until just combined. Be careful not to overmix, as this can make the blondies tough instead of chewy. The batter will be thick, but that is normal.

Step 3: Spread the Batter in the Pan

Transfer the batter into the prepared baking pan. Use a spatula to spread it evenly into the corners, ensuring a uniform thickness so the bars bake evenly.

Step 4: Add the Cinnamon-Sugar Topping

In a small bowl, mix the granulated sugar and cinnamon together. Sprinkle the mixture evenly over the batter, creating a sweet, slightly crunchy top layer. This step mimics the classic snickerdoodle flavor without requiring individual cookie rolling.

Step 5: Bake the Blondies

Place the baking pan in the preheated oven and bake for 25-30 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out with a few moist crumbs. If the toothpick comes out completely clean, the bars may be slightly overbaked, so it is best to remove them when they are still soft in the center.

Step 6: Cool and Slice

Allow the blondies to cool in the pan for at least 15-20 minutes before slicing. Cutting them too soon may cause them to fall apart. Once cooled, cut them into squares or rectangles, depending on your preference.