Gather the ingredients. Preheat the oven to 350°F (175°C). Coarsely chop the 115 g unsweetened chocolate. Coarsely chop the 120 g pecans.
The Brownies
Create a double boiler by filling a saucepan with about an inch of water and bringing it to a simmer over medium heat. Place a large heatproof bowl on top, ensuring the bottom of the bowl does not touch the water. Add the 115 g unsweetened chocolate and 170 g unsalted butter to the bowl.
Stir occasionally until both are completely melted and the mixture is smooth.
Remove the bowl from the heat. Stir in the 200 g sugar and 200 g brown sugar until well combined.
Beat in the 3 eggs, one at a time, followed by the 1 tsp. vanilla extract.
Add the 120 g all-purpose flour, ¼ tsp. salt, and the 120 g pecans. Mix with a spatula until just combined. Do not overmix.
The Baking
Line a baking pan with parchment paper, leaving enough overhang on the sides to act as handles. Lightly butter the paper and sides. Pour the batter into the prepared pan and spread it evenly.
Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out with moist, fudgy crumbs attached. Be careful not to overbake. Let the brownies cool completely in the pan on a wire rack.
The Serving
Once cooled, use the parchment handles to lift the brownies out of the pan and cut into 24 squares and serve.
Enjoy your Baker's One-Bowl Brownies [Brownies en un bol de Baker] with a nice glass of milk or tea or coffee if lactose isn't your friend.