Brownies are a classic bake sale treat. A combination of unsweetened chocolate and chocolate chips gives these brownies extra chocolate flavor.
Adjust oven rack to lowest position and heat oven to 350 degrees. Make aluminum foil sling for 13-by-9-inch metal baking pan. Spray foil lightly with vegetable oil spray.
In medium bowl, whisk together flour, baking powder, and salt.
Place unsweetened chocolate in large zipper-lock plastic bag and seal. Use rolling pin to gently pound chocolate into small pieces.
In large microwave-safe bowl, combine butter and unsweetened chocolate. Heat in microwave at 50 percent power for 1 minute. Stop microwave and stir mixture with rubber spatula to combine. Heat in microwave at 50 percent power until melted, about 1 minute. Remove bowl from microwave and whisk until smooth.
Add sugar, eggs, and vanilla to chocolate mixture and whisk until smooth.
Add flour mixture and use rubber spatula to gently stir until just combined. Stir in chocolate chips. Scrape batter into prepared baking pan.
Place baking pan in oven. Bake brownies until toothpick inserted in center comes out with few moist crumbs attached, 30 to 35 minutes.
Use oven mitts to remove baking pan from oven (ask an adult for help). Place baking pan on cooling rack and let brownies cool in pan for 1½ hours.
The chocolate chips create gooey pockets of melted chocolate in these deluxe brownies. To switch it up, try using ½ cup of your favorite baking chips—such as peanut butter or butterscotch chips—in place of the chocolate chips in step 6.
Bittersweet chocolate chips have better chocolate flavor than the usual semisweet chips, but either will work in our recipes. Milk chocolate chips are altogether different (they contain milk solids) and should not be used in recipes unless called for by name.