Directions

1. Place a rack in the lower third of the oven and preheat the oven to 325°F. Line the bottom and sides of an 8×8-inch square baking pan with parchment paper or foil, leaving an overhang on two opposite sides.

2. Place the butter and cocoa powder in a microwave-safe bowl, and warm, stirring every 30 seconds or so, until melted. Mix with sugar and salt, stirring well until combined. Or combine the butter, sugar, cocoa, and salt in a medium heatproof bowl and set the bowl in a wide skillet of barely simmering water. Stir from time to time until the butter is melted and the mixture is smooth and hot enough that you want to remove your finger quickly after dipping it in to test.

3. Both methods: Set the bowl aside briefly until the mixture is only warm, not hot. It will look gritty at this point, but it will smooth out once the eggs and flour are added.

4. Stir in the vanilla with a wooden spoon. Add the eggs one at a time, stirring vigorously after each one. When the batter looks thick, shiny, and well blended, add the masa harina and cinnamon and stir until you cannot see it any longer, then beat vigorously for 40 strokes with the wooden spoon or a rubber spatula. No need to worry about overmixing, since there’s no risk of gluten developing here.

5. Bake until a toothpick plunged into the center emerges slightly moist with batter, 30-35 minutes. Let cool completely on a rack, or move to the fridge or freezer for about half an hour (this will allow you to cut clean lines).

6. Lift up the ends of the parchment or foil liner, and transfer the brownies to a cutting board. Cut into 16 or 25 squares.