Preheat your oven to 350°F (175°C) to ensure even baking.
Coat a 9x13 inch baking pan with 1 tablespoon of butter, covering all sides to prevent sticking.
In a large mixing bowl, whisk together 2 3/4 cups all-purpose flour, 2 cups sugar, 2 teaspoons baking powder, 1 1/2 teaspoons baking soda, and 1 teaspoon kosher salt until well combined.
In another bowl, beat 3 large eggs, 3/4 cup melted butter, and 1/2 teaspoon vanilla extract until smooth.
Gradually add the wet ingredients to the dry mixture, stirring gently until just combined. Do not overmix; a few lumps are okay.
Gently fold in 1 cup chopped pecans, distributing them evenly throughout the batter.
Pour the batter into the prepared baking pan and spread it evenly. Bake for approximately 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the bars from the oven and allow them to cool in the pan for about 10 minutes. Then transfer them to a cooling rack to cool completely.