Set your oven to 350°F (175°C) and allow it to fully preheat while you prepare the batter. Grease a 9x13-inch baking pan with butter or non-stick spray, or line it with parchment paper for easy removal. A properly greased pan ensures the blondies don’t stick and come out cleanly.

In a large mixing bowl, stir together 1 cup of melted butter, 1 cup of brown sugar, and ½ cup of granulated sugar. Mix until the sugars dissolve and the mixture becomes smooth and creamy. Add 2 large eggs and 2 teaspoons of vanilla extract, stirring until fully incorporated. The eggs provide structure, while the vanilla enhances the flavor.

In a separate bowl, whisk together 2 ½ cups of all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and ½ teaspoon of salt. Gradually add the dry mixture to the wet ingredients, stirring gently until just combined. Avoid over-mixing, as this can make the blondies dense instead of soft and chewy.

In a small bowl, mix ¼ cup of granulated sugar with 1 tablespoon of ground cinnamon. This blend creates a sweet and slightly crunchy topping that enhances the blondies’ flavor. You can adjust the cinnamon-to-sugar ratio based on your preference for a stronger or milder spice.

Spread the batter evenly into the prepared baking pan, using a spatula to smooth out the surface. Evenly sprinkle the cinnamon-sugar mixture over the top, ensuring full coverage for a flavorful crust. Lightly pressing the topping into the batter can help it adhere better during baking.

Place the pan in the preheated oven and bake for 25–30 minutes. Check for doneness by inserting a toothpick in the center—if it comes out clean or with a few moist crumbs, the blondies are ready. Avoid overbaking, as they will continue to firm up as they cool.

Let the blondies cool completely in the pan before slicing them into squares. This helps them set properly and prevents them from crumbling. For clean cuts, use a sharp knife and wipe it between slices. Enjoy these cinnamon sugar blondies with a glass of milk or a cup of coffee!