Step 1

Heat the oven to 350°F and arrange a rack in the middle. Line an 8-by-8-inch metal baking pan with aluminum foil.

Step 2

Combine the chocolate and butter in a medium saucepan and cook over low heat, stirring frequently, until melted and smooth. Remove from the heat and let cool slightly, about 5 minutes. (Alternatively, melt the chocolate and butter in the microwave, stirring every 30 seconds, A lot easier and quicker!!)

Step 3

Combine the eggs, sugar, vanilla, baking powder, and salt in a large bowl and stir with a rubber spatula until just evenly incorporated.

Step 4

Add the chocolate mixture and stir until evenly combined.

Step 5

Add the flour and fold in until just incorporated, about 20 strokes (no white streaks should remain). (Add in the walnuts nuts either before you put it in the pan or after whether you want them on top or mixed in)

Step 6

Pour the batter into the prepared pan, push it to the edges in an even layer, and smooth the top.

Step 7

Bake until a cake tester or skewer inserted into the center comes out clean, about 25 minutes.

Step 8

Remove to a wire rack and let the brownies cool for at least 20 minutes.

Step 9

Serve.