Preheat your oven: Set your oven to 350°F (175°C) to get the perfect baking temperature.

Prepare the baking pan: Line a 9x13 inch baking pan with parchment paper, leaving some overhang to easily lift the brownies out later. Lightly grease the parchment paper.

Melt the butter: In a large saucepan, melt the butter over medium heat. Once melted, remove from heat and let it cool slightly.

Mix in the sugar and eggs: Add the granulated sugar to the melted butter and whisk until combined. Beat in the eggs one at a time, ensuring each egg is fully incorporated before adding the next.

Sift dry ingredients: In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. This ensures no lumps.

Combine wet and dry ingredients: Gradually add the dry mixture to the wet mixture, stirring until just combined. Be careful not to overmix.

Add vanilla, chocolate, and nuts: Stir in the vanilla extract, then gently fold in the chocolate chips and chopped nuts if using.

Bake the brownies: Pour the batter into the prepared baking pan, smoothing the top with a spatula. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

Cool and slice: Let the brownies cool in the pan for about 15 minutes. Use the parchment overhangs to lift the brownies out of the pan and transfer to a wire rack to cool completely. Slice into squares and enjoy!