Preheat the oven to 350°F. Grease an 8" square pan or 9" round pan; either should be at least 2" deep.
Place the sugar, butter, and salt in a microwave-safe bowl or saucepan. Heat over medium heat, stirring with a heatproof spatula until the butter melts and the mixture lightens in color. This step helps melt the sugar, which will give the brownies a shiny crust.
If you've heated the sugar and butter in a saucepan, transfer the mixture to a bowl; otherwise, just leave the hot ingredients right in their microwave-safe bowl. Blend in the vanilla and cocoa, then add the eggs and mix until shiny.
Blend in the flour and the baking powder. Stir in the chips and/or nuts, if you're using them.
Pour the batter into the prepared pan, spreading it to the edges.
Bake the brownies for 33 to 38 minutes, until the top is set; and a cake tester or toothpick inserted in the center comes out clean or nearly so, with perhaps a few wet crumbs, or a tiny touch of chocolate at the tip of the tester.
Remove from the oven and cool for about 15 minutes before cutting. Once the brownies are cool, cover tightly with plastic.
Tips from our Bakers
Use superfine sugar for wonderfully moist, fudgy brownies. Unlike superfine sugar, granulated sugar doesn't dissolve completely in the butter; brownies made with granulated sugar will tend toward cakey rather than fudgy.
- Can you dig in to these brownies immediately? Of course. You can't slice them, but you can certainly sample with a spoon. For easiest slicing, wait at least 15 minutes before serving. And for prettiest (crumb-free) servings, wait till brownies are completely cool before cutting.
- What's the difference in baking time using a metal vs. glass vs. stoneware pan? We noticed very little difference in our side-by-side test; the brownies in a thick stoneware pan needed about 1 additional minute in the oven, but the brownies in the medium-gray (not dark) metal pan, and in glass, baked for the same amount of time. If you're using a dark metal pan, or one that you know bakes faster or slower than your recipe usually indicates, adjust the baking time for these brownies accordingly.
You can easily make these brownies dairy-free. Simply substitute your favorite vegan butter 1:1 by volume for the dairy butter called for in the recipe, no other changes necessary.