1. Preheat the oven to 350°F. Grease a 9-inch square baking pan.
2. Chop the chocolate. Place the chocolate and butter in the bowl fitted with the kneading/crushing blade. Launch at speed 3 at 110°F for 10 minutes. If chocolate is not fully melted, scrape down the sides of the bowl and relaunch for another 2 minutes.
3. Scrape down the sides of the bowl. Add sugar, flour, baking powder, eggs, vanilla and pecans. Launch at speed 4 for 1 minute. Scrape down the sides of the bowl and relaunch at speed 8 for 2 minutes.
4. Spread batter into the prepared pan. Bake for 20-25 minutes or until edges look dry and center is almost set. Do not overbake. Cool before cutting.