- Preheat oven to 350°F. Grease a 13 x 9 x 2 baking pan and line the bottom with parchment paper. Set aside.
- In a medium saucepan, heat the brown sugar and the butter over medium heat until the butter melts and the mixture is smooth. Let it cool slightly.
- Add one egg to the butter/sugar mixture and beat until combined. Repeat with the second egg. Add the vanilla extract and beat to combine.
- In a large bowl, whisk the flour, baking powder, baking soda, and salt together. Make a well in the center and pour the egg/butter/sugar mixture into the middle. Using a whisk, slowly stir the wet into the dry until almost all the flour has been mixed in, then fold in the rest of the flour and beat until combined.
- Pour into your prepared baking dish. With an oil off-set spatula, spread the mixture evenly. Sprinkle the top with chopped walnuts.
- Bake for 25 to 30 minutes or until a toothpick comes out clean from the center.
- Let it cool a little in the pan. You can cut them into bars while it’s still warm but it’s better to wait until they’ve completely cooled. Are you listening to me? No? Okay. Makes about 24 small bars or one large serving.