PreparationFor brownies: Preheat oven to 325°F. Fold 16-inch-long piece of foil to 8x16-inch strip; place in 8x8x2-inch metal baking pan, leaving overhang on 2 sides. Repeat with another sheet of foil in opposite direction, lining pan completely. Spray foil with nonstick spray. Stir butter and chocolate in heavy large saucepan over very low heat until chocolate is melted. Remove from heat; whisk in sugar, then eggs, 1 at a time. Whisk in espresso powder, vanilla, and salt; sift flour over and stir to blend well. Transfer batter to prepared pan. Bake brownies until puffed and dry-looking and tester inserted into center comes out with some moist batter attached, about 35 minutes; cool completely in pan on rack. For ganache: Place white chocolate in medium microwave-safe bowl. Bring cream to simmer in small saucepan. Pour cream over chocolate in bowl. Let stand 30 seconds, then stir until chocolate is melted and smooth. If necessary, microwave on low power in 10-second intervals until white chocolate is melted completely. Chill until ganache is thick but still slightly pourable, about 25 minutes. Using foil as aid, lift brownies from pan. Turn over onto sheet of parchment paper; peel off foil. Pour ganache onto center of brownies; spread to edges (some may drip over). Sprinkle with cinnamon. Chill until ganache is set, at least 2 hours. DO AHEAD: Can be made 2 days ahead. Cover and keep chilled. Cut brownies into 4 strips. Cut each strip crosswise into 5 or 6 pieces, or cut each strip into 6 triangles. Arrange brownies on platter and serve.
PreparationFor brownies: Preheat oven to 325°F. Fold 16-inch-long piece of foil to 8x16-inch strip; place in 8x8x2-inch metal baking pan, leaving overhang on 2 sides. Repeat with another sheet of foil in opposite direction, lining pan completely. Spray foil with nonstick spray. Stir butter and chocolate in heavy large saucepan over very low heat until chocolate is melted. Remove from heat; whisk in sugar, then eggs, 1 at a time. Whisk in espresso powder, vanilla, and salt; sift flour over and stir to blend well. Transfer batter to prepared pan. Bake brownies until puffed and dry-looking and tester inserted into center comes out with some moist batter attached, about 35 minutes; cool completely in pan on rack. For ganache: Place white chocolate in medium microwave-safe bowl. Bring cream to simmer in small saucepan. Pour cream over chocolate in bowl. Let stand 30 seconds, then stir until chocolate is melted and smooth. If necessary, microwave on low power in 10-second intervals until white chocolate is melted completely. Chill until ganache is thick but still slightly pourable, about 25 minutes. Using foil as aid, lift brownies from pan. Turn over onto sheet of parchment paper; peel off foil. Pour ganache onto center of brownies; spread to edges (some may drip over). Sprinkle with cinnamon. Chill until ganache is set, at least 2 hours. DO AHEAD: Can be made 2 days ahead. Cover and keep chilled. Cut brownies into 4 strips. Cut each strip crosswise into 5 or 6 pieces, or cut each strip into 6 triangles. Arrange brownies on platter and serve.