Preheat the oven to 350°F (175°C). Lightly grease a 9x13-inch rectangular baking dish, or line the base with parchment paper for easy removal.
In a large bowl, whisk together the granulated sugar, brown sugar, oil or melted butter, and eggs until the mixture becomes smooth and well-blended.
In a separate medium bowl, combine the flour, baking powder, and salt. Stir these dry ingredients together until evenly mixed.
Gradually incorporate the flour mixture into the bowl with the wet ingredients, stirring just until everything is fully incorporated. Avoid over-mixing.
Add the vanilla extract and blend briefly to distribute the flavor evenly.
Fold in the chopped pecans gently, ensuring they are spread consistently throughout the batter.
Transfer the batter to the prepared baking dish, smoothing the top with a spatula. Place in the preheated oven and bake for 30 to 35 minutes, or until the surface is golden and a toothpick inserted into the center emerges clean.
Once baked, allow the loaf to cool completely in the pan before slicing into squares or bars. Serve at room temperature or lightly warmed for best taste and texture.