Nana's Brownies

Preparation

1. Brownies:

   Step 1

   Preheat oven to 350°F. Butter and flour an 8x8" baking dish, shaking out excess flour. Toast walnuts, if using, on a rimmed baking sheet, tossing occasionally, until golden brown, 8–10 minutes; let cool. Increase oven temperature to 375°F.

   Step 2

   Whisk cocoa, salt, baking powder, and 1 cup flour in a medium bowl to combine and work out any lumps. Heat chocolate, sugar, and 1/2 cup butter in a large heatproof bowl set over a saucepan of simmering water (bowl should not touch water), stirring constantly, until smooth. Remove from heat and add eggs one at a time, beating vigorously with a wooden spoon to blend after each addition. Mix in vanilla, then add dry ingredients and mix until just combined. Fold in reserved walnuts (do not overmix).

   Step 3

   Scrape batter into prepared pan; smooth top. Bake until a tester inserted into the center comes out clean, 30–40 minutes. Let cool.

2. Glaze:

   Step 4

   Heat chocolate, butter, rum, cocoa powder, vanilla, and salt in a heatproof bowl set over a saucepan of simmering water (bowl should not touch water), stirring constantly, until smooth.

   Step 5

   Pour glaze over brownies and top with walnuts, if using. Chill until glaze is set, at least 1 hour. Slice into 12 brownies.

3. Do Ahead

   Step 6

   Brownies can be made 1 day ahead. Keep chilled.