Preheat oven to 350°. Grease a baking pan.
In a medium sauce pan, heat and stir brown sugar and butter until the latter melts and mixture is smooth. Cool slightly.
Stir in the eggs, one at a time.
Stir in vanilla, then the flour, baking powder and baking soda.
Spread the batter into the greased pan.
Sprinkle the chopped pecans on top. Bake for 25 to 30 minutes or test with a toothpick. It’s done when the toothpick comes out clean.