While we'd never knock classic brownies, we tend to think of a bowl of chocolate-rich batter as a blank slate for experimentation — more is more, right? With your trusty recipe  in hand (or a solid box mix , no judgment here) the options are as great as your imagination is vast. Here are a few of our favorite ideas:
Swirl It In
- Master your marbling technique: For a picture-perfect swirl, spread the brownie batter into a pan, then dollop 1/4 to 1/2 cup of your mix-in of choice on top. Using the tip of a butter knife swirl it into the batter, folding some under the surface of the batter. Basically anything saucy that pairs well with chocolate works here. Try salted caramel sauce, your favorite nut butter (Nutella, anyone?), or raspberry jam. Or, for a tangy cheesecake swirl, mix together 4 ounces of room-temperature cream cheese, 3 tablespoons sugar, and a splash of vanilla before dolloping it onto the brownie batter.
- Have fun with flavor: Add a dash of peppermint extract (and crushed candy canes for bonus points) or go the Mexican hot chocolate route and sprinkle in cinnamon and cayenne pepper to taste. Just remember that both of these options are very potent, so start with less than you think you'll need; you can always add more.
Fold In Some Goodies
Add about 1 1/2 cups of any of the following to the batter before spreading it in the pan:
- Double up on chocolate: Chocolate chunks or chips melt into puddles of molten chocolate once baked. Any chocolate will work, but for an ultraluxe option, fold in spiced chips from La Boite . To add bitter bite and crunch, substitute 1/2 cup of chocolate chips for cacao nibs.
- Go nuts: Chopped, toasted walnuts, pecans, hazelnuts, almonds, or peanuts add nutty flavor and crunch.
- Take a trip down the candy aisle: M&M's (pretty much any flavor  will work) and Reese's Pieces add color and crunch; chopped up Reese's Peanut Butter Cups, Peppermint Patties, Rolos, and the like never fail; or, for a different take on caramel brownies, add diced chewy caramels. Or, to channel s'mores, layer minimarshmallows on top of almost-baked brownies and broil until toasty brown.
Spread It on Thick
- Once completely cooled, drizzle your batch of brownies with dark-chocolate ganache, or slather them with chocolate, caramel, or peanut butter frosting.