Sarah Kieffer's 100 Cookies includes quite a few brownie recipes. There are base recipes ("My Favorite Brownies," "Fudgy Brownies," "Cakey Brownies," and even "White Chocolate Brownies"), and then a lot of variations involving add-ins like cream cheese, caramel, nuts, peanut butter, etc. I decided to jump right in to the chocolate brownie variations.
First, I tried the "Rocky Road Brownies," which add chocolate chips, pecans, and marshmallows to the "My Favorite Brownies" base recipe. To make the batter, you whisk together eggs, granulated sugar, brown sugar, canola oil, and vanilla; incorporate a mixture of bittersweet chocolate and butter that were melted in a double boiler, with cocoa added; stir in flour, salt, and baking powder; and add chopped toasted pecans, chocolate chips, and mini marshmallows (I didn't have mini marshmallows, so I used regular Jet Puffed marshmallows that I cut into quarters). You pour the batter into a parchment-lined pan; sprinkle over more pecans, chocolate chips, and marshmallows; and bake.
A few days later I made Kieffer's "Marshmallow Peanut Butter Brownies," which use the same brownie base recipe and add a swirl of peanut butter filling and store-bought marshmallow fluff on top before baking. You make the same brownie batter as the rocky road brownies, but don't add the pecans, chocolate chips, or marshmallows. Instead, you spread the plain brownie batter in a parchment-lined pan; add dollops of marshmallow fluff and a peanut butter filling (creamy peanut butter, powdered, sugar, butter, vanilla, and salt); and swirl the filling and marshmallow together with the batter before baking.
here on Sarah's blog alongside the recipe) shows brownies with a bright white marshmallow swirl.
Even though these two brownies are based on the same recipe, I had very different opinions of them. I was underwhelmed with marshmallow-peanut butter version, although I think in significant part this was because I loved the rocky road brownies so much. I thought the marshmallow-peanut butter brownies really could have benefited from something to add texture -- maybe some chopped peanuts mixed into the brownie batter, or even using crunchy peanut butter instead of creamy in the topping. I also thought that the strong flavor of the peanut butter competed with the chocolate flavor of the brownie a bit.
Don't get me wrong, the marshmallow-peanut butter brownie is perfectly tasty. But the rocky road brownie is the one I still dream about.