Preheat the oven to 350°F. Cream together the softened butter and brown sugar in a large mixing bowl until light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour and baking powder. Gradually add the dry mixture to the wet ingredients, stirring until just combined. Avoid over-mixing to maintain a chewy texture.

Grease and flour a 9-inch round cake pan, ensuring the entire surface is covered to prevent sticking.

Pour the batter into the prepared pan, spreading it evenly with a spatula to ensure a uniform thickness.

Place the pan in the preheated oven and bake for 25-30 minutes. The blondies are ready when the edges are golden and a toothpick inserted into the center comes out with a few moist crumbs.

Allow the blondies to cool in the pan for at least 10 minutes before transferring them to a wire rack to cool completely.

Cut into slices and serve warm, optionally paired with a scoop of vanilla ice cream for a classic dessert experience.

Store any leftover blondies in an airtight container at room temperature for up to 5 days to maintain freshness.