Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan.

In a large mixing bowl, combine the melted butter and granulated sugar. Mix well until fully combined.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

If desired, fold in the chocolate chips or chopped nuts.

Pour the batter into the prepared loaf pan, spreading it evenly.

Bake in the preheated oven for about 50-60 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Remove the brownie loaf from the oven and allow it to cool in the pan for about 10 minutes.

Afterward, transfer the brownie loaf to a wire rack to cool completely before slicing and serving