Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish.
In a large bowl, combine the self-rising flour, brown sugar, and granulated sugar.
Add chopped pecans and stir until evenly distributed.
In a separate bowl, whisk together the vegetable oil, eggs, and vanilla extract.
Pour the wet ingredients into the dry ingredients and mix until just combined.
Spread the batter evenly in the prepared baking dish.
Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Let cool slightly before serving. Enjoy warm or at room temperature.