Prescription-Strength Fudge Brownies

12 Tbs. (6 oz.) unsalted butter, cut in big pieces
3/4 cup (2 1/4 oz.) unsweetened cocoa powder (natural or Dutch-process), sifted if lumpy
1 1/2 cups sugar
1/4 tsp. table salt
2 large eggs
1 1/2 teaspoons pure vanilla extract
3/4 cup (3 1/2 oz.) a-p flour
1/2 cup topping (optional): semisweet, peanut butter, or white chocolate chips, coarsely chopped nuts, chopped peppermint candies; you can also stir in another 1/2 cup chips into the batter

1. Position rack on middle rung and heat oven to 350F. Lightly grease sides and bottom of an 8-inch square baking dish.

2. Put the butter in a medium saucepan and set over medium-high heat, stirring occasionally, until the butter is melted. Slide the pan from the heat and add the cocoa; whisk until smooth. Add the sugar and salt,; whisk until blended. Add the eggs one at a time, whisking after each addition until blended. Whisk in the vanilla with the second egg. Sprinkle the flour over the top and stir with a rubber spatula just until blended.

3. Scrape the batter into the pan and spread evenly. Scatter the topping evenly over the top if use. Bake until a toothpick inserted into the center comes out with small, gooey clumps of brownie sticking to it, about 32 minutes. Don't over bake of the brownies won't be fudgy. Transfer dish to a rack to cool. Use a bench scraper to cut the cooled brownie into 3 equal strips and then cut each strip into four equal pieces. (Or freeze uncut: after cooling for about 20 minutes, invert onto a rack, let cool completely, and wrap tightly; freeze for up to 1 month).

Source of recipe: The Weekend Baker, Abigail Johnson Dodge