Luckily, America's Test Kitchen solved this dilemma for me. (note: I learn so much from that show. You should watch it on your local PBS station if you don't already). They did a show about chocolate a couple of years ago and it featured a chewy brownie recipe. They explained why homemade brownies are not chewy but boxed brownies are. It has to do with the amount of saturated vs unsaturated fat in a brownie. If you've ever made a homemade brownie, you probably used butter (a saturated fat), but if you've made a box brownie you know you use oil (unsaturated). A higher ratio of unsaturated fat is what produces a chewy brownie. You can read more about it here.
So, since watching the show I now use their recipe every time I bake brownies. Whew! Now, I can really say that I do bake everything from scratch. The great thing about this recipe is that it's almost as easy as using a brownie mix. There is no mixer required and it's made in only one bowl.
Well, make that two bowls, if you choose to add this decadent peanut butter filling (and you should). To make the ultimate brownie, I like to add a peanut butter filling that I've been using for a while from Martha Stewart.
The nice part about the recipe I have below is that you can make it as is for the best peanut butter brownies, or you can omit the peanut butter filling and just make the rest of the recipe and you'll have the best chocolate brownies (you may need to reduce baking time by a few minutes). Or, if you are pressed for time, there's no shame in using a boxed brownie mix. Just whip up the peanut butter filling and swirl it into the batter as I've stated below and people will still be thanking you for the great brownies. I like to use Ghirardelli brownie mix as I think it has better chocolate flavor than other grocery store brands.
Peanut Butter Brownies
1/3 cup unsweetened cocoa powder
1½ teaspoons instant espresso powder
½ cup plus 2 tablespoons boiling water
2 ounces unsweetened chocolate, finely chopped
4 tablespoons unsalted butter, melted
½ cup plus 2 tablespoons vegetable oil
2 large eggs
2 large egg yolks
2 teaspoons vanilla extract
2½ cups sugar
1¾ cups all-purpose flour
¾ teaspoon salt
1 cup bittersweet chocolate chips, or bittersweet chocolate cut into ½" pieces
Peanut Butter Filling
6 tablespoons melted butter
1 cup plus 2 tablespoons smooth peanut butter (do not use natural peanut butter)
¾ cup confectioners' sugar
¾ teaspoon vanilla
¼ teaspoon salt
Adjust rack to lowest position in oven and heat to 350 degrees. Line a 9 x 13 inch metal baking pan with foil leaving an overhang on all sides (this will help you remove the brownies from the pan later). Spray foil liberally with cooking spray.
Make brownie batter: Whisk cocoa, espresso powder and boiling water together in a large bowl until smooth. Add unsweetened chocolate and whisk until melted. Whisk in butter and oil (it's okay if the mixture looks curdled). Whisk in eggs, yolks and vanilla until smooth. Whisk in sugar until incorporated. Whisk in salt. Fold in flour with rubber spatula until combined. Fold in chocolate chips or pieces.
Make peanut butter filling: Whisk together all ingredients until smooth.
Pour half brownie batter into pan. Dollop half of peanut butter filling on top of batter in 12 evenly spaced mounds (no, it doesn't have to be perfect). Pour remaining brownie batter into the pan. Dollop the rest of the peanut butter filling on top of batter in 12 evenly spaced mounds. Using a butter knife swirl the batter to create a marbleized effect, being sure to gently touch the bottom of the pan to ensure that all the peanut butter is swirled into the batter.
Bake for 30 -35 minutes, rotating the pan halfway through baking, until a toothpick inserted halfway between the center and edge of the pan (you can see where I inserted the toothpick in the photo below) comes out with just a few moist crumbs.
Makes 24 brownies.
Notes: Keep in an airtight container at room temperature for up to four days. If you use a glass pan instead of a metal pan, remove the brownies from the pan (but keep in sling) 10 minutes after baking otherwise the heat retention of the glass can cause them to over bake.