Preheat your oven to 350 degrees F and line a 13x9in. baking dish with foil or parchment paper, leaving enough overhang so that the cinnamon bars are easy to pull out later. Spray the foil with a nonstick spray and set aside.

In a large saucepan, combine the brown sugar and butter. Heat the mixture over medium-low heat and stir constantly until both ingredients have melted, about 10 minutes. Remove from heat and set aside to cool slightly, about 10 minutes.

In a large bowl, whisk together the flour, cinnamon, baking powder, baking soda, nutmeg and salt. Set aside.

To the saucepan with the butter and sugar, add each egg, one at a time. Make sure to fully incorporate each egg before adding the next. Whisk in the vanilla extract. Pour it into a large bowl, and slowly add the flour mixture. Fold the ingredients together until moistened.

Pour the mixture into your prepared pan and bake for 45 minutes. Remove from heat and set aside on a wire rack to cool slightly.

In a small bowl, stir together the sugar and cinnamon for the topping. Drizzle the melted butter onto the cinnamon bars and spread with the back of a spoon. Sprinkle the cinnamon/sugar mixture on top.

Let the bars cool completely at this point. Once cool, remove the bars with the foil overhang and cut into bars. Store at room temperature for about 3 days.

Enjoy!