- Preheat your oven to 325 degrees Fahrenheit. 
- Butter an 8-inch square baking dish using 1 teaspoon of butter. 
- Cut a piece of parchment paper to line the bottom and two sides of your prepared dish. 
- In a medium bowl, mix the sugar, melted butter, eggs, and vanilla extract until well combined. 
- Use a spoon or whisk to ensure these ingredients are thoroughly blended. 
- Combine the unsweetened cocoa powder, all-purpose flour, salt, and baking powder in a separate bowl. 
- Gradually add this dry mixture to the wet ingredients, stirring until just combined. 
- Gently fold in the chopped nuts if you're using them. 
- Spread the batter evenly into the prepared baking dish, smoothing the top with a spatula. 
- Bake the brownies in the preheated oven for about 20-25 minutes. 
- Ensure a toothpick inserted into the center comes out with a few moist crumbs before removing.