Food & Cooking Recipes Dessert & Treats Recipes Brownie Recipes Big-Batch Triple-Chocolate Brownie Bars Be the first to rate & review! By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on December 11, 2018 Print Rate It Share Share Tweet Pin Email Prep Time: 35 mins Total Time: 1 hr 5 mins Yield: 54 Whether you're taking them to an event or like to stock homemade sweets for your crew, these sheet-pan bar cookies, which keep for up to a month in the freezer, are the ticket. They include bittersweet and white chocolates and cocoa powder, plus goodies like nuts and dried fruit. To serve, simply let them come to room temperature. Ingredients 3 sticks unsalted butter, cubed, plus more, softened, for sheet 3 cups unbleached all-purpose flour ¼ cup Dutch-process cocoa powder 1 ½ teaspoons baking soda 1 ½ teaspoons kosher salt 1 pound bittersweet chocolate, coarsely chopped (3 cups) 1 cup granulated sugar 1 ½ cups packed light-brown sugar 3 large eggs, room temperature 2 teaspoons pure vanilla extract 8 ounces roasted unsalted nuts, such as peanuts, pecans, or walnuts, coarsely chopped (1 ⅔ cups) 6 ounces dried fruits, such as raisins, currants, or cherries (1 ¼ cups) 4 ounces white chocolate, coarsely chopped (¾ cup) Directions Preheat oven to 350 degrees. Brush a 13-by-18-inch rimmed baking sheet with butter. In a bowl, whisk together flour, cocoa, baking soda, and salt until thoroughly combined. In a large heatproof bowl set over a pot of simmering water, melt butter with 10 ounces (2 cups) bittersweet chocolate. Remove from heat; stir until smooth. Let cool 5 minutes. Add both sugars, eggs, and vanilla and beat on medium speed, or whisk vigorously by hand, until thickened slightly and glossy, 2 to 3 minutes. Reduce speed to low; beat in flour mixture just until combined. Stir in two-thirds of nuts and dried fruits. Transfer batter to prepared sheet, spreading evenly to edges. Sprinkle evenly with white chocolate and remaining nuts, dried fruits, and 1 cup bittersweet chocolate. Gently press toppings into batter with flattened palms. Bake until edges are puffed and just set but center is still wobbly, 20 to 23 minutes. Transfer pan to a wire rack; let cool completely. Cut lengthwise into thirds, then crosswise into 1-inch-thick rectangles. Bars can be stored in an airtight container at room temperature up to 5 days, or stacked between layers of parchment in a freezer bag and frozen up to 1 month. (Thaw at room temperature before serving.) Marcus Nilsson Cook's Notes You can use any combination of nuts and dried fruits, or skip them entirely. For the best flavor and texture, make the bars at least one day ahead. Rate it Print