• Preheat the oven to 350 degrees Fahrenheit and grease a 15x10x1 inch pan with nonstick cooking spray.
• Whisk 2 cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon salt, and 1 ½ teaspoons ground cinnamon together in a medium bowl. Set aside.
• Add 1 ½ cups granulated sugar, 1 cup vegetable oil, and 3 large eggs to a large mixing bowl and whisk together until smooth. Add the flour mixture and mix until just incorporated.
• Stir in 2 cups shredded zucchini and 1 ½ cups chopped pecans. Spread evenly in the prepared pan.
• Bake for 30-40 minutes, until a toothpick inserted in the center comes out clean. Let the bars cool completely.

Brown Butter Frosting

• Heat a medium-sized saucepan over medium heat. Add 6 tablespoons unsalted butter to the pan and cook, stirring occasionally, until it begins to brown, about 5 to 8 minutes. Remove the butter to cool slightly.
• Use a hand mixer to combine the browned butter with 6 cups powdered sugarand 1 teaspoon vanilla extract. Add 8-10 tablespoons milk until smooth and spreadable. Spread evenly over the cooled bars and serve.