These cast iron walnut brownies are fudgy and rich, with crisp edges. Made from scratch with simple pantry staples, these brownies are easy to whip up in your own home.
If you love walnut brownies and have a cast iron skillet, you must give this recipe a try! Baking in cast iron gives these brownies a buttery, crunchy crust that pairs perfectly with the moist, dense and fudgy middle.
Brownies make the perfect beginner baker recipe because they don't require any leavening agents and are generally very forgiving. All you need for this recipe is a 10 inch cast iron skillet and a few pantry staples.
These brownies turn out extra chocolatey, fudgy, and rich. Perfect for any brownie lover! They're best served warm, with a scoop of vanilla ice cream on top.
Ingredients and substitutions
- Unsalted butter - can be substituted with salted butter, but you'll want to reduce the amount of salt by ¼ teaspoon.
- Sugars - you'll need granulated and brown sugars for this recipe. Granulated sugar helps give these brownies a crunchy crust and chewy texture, while the molasses in brown sugar adds depth of flavor and makes them more fudgy.
- Vanilla extract - Adds depth of flavor to the brownies.
- Eggs - To quickly bring eggs to room temperature, add your eggs (in the shell) to a bowl, and fill with warm tap water. This will warm your eggs up in just a few minutes.
- All-purpose flour - I've only tested this recipe using all-purpose flour. I do not recommend making any substitutions as this can change the texture and consistency of your brownies.
- Cocoa powder - I used natural cocoa powder, but dutch cocoa powder would also work in this recipe (since there are no leavening agents).
- Salt - Enhances the flavor of the brownies.
- Optional mix-ins: I like adding mini chocolate chips and chopped walnuts, but feel free to substitute with your favorite mix-ins, like M&M's candies, white chocolate chips, pecans, peanuts, or a few crumbled oreo cookies.
What makes brownies fudgy?
These brownies are made with plenty of fats, like butter and chocolate chips, and less flour, which makes them fudgy, rich, and dense.
A cakier brownie will include more flour and sometimes a leavening agent to help them rise slightly.
What kind of pan to use
This recipe is written using a 10 inch cast iron skillet. Here's the exact skillet I'm using in the photos:
- Lodge L8SK3 10-¼-Inch Pre-Seasoned Skillet (79 sq inches)
This recipe will also work in the in the following pan sizes:
- 8x8 square baking pan (64 sq inches) - brownies will be thicker
- 9x9 square baking pan (81 sq inches)
If you'd like to use a square pan instead, I suggest following my dark chocolate walnut brownies recipe. Both recipes use the same ingredients (don't mess with success!).
I like to add mini chocolate chips and chopped walnuts to my skillet brownies. However, you're welcome to make this recipe your own with all sorts of optional mix-ins:
- White chocolate chips
- Chopped peanuts
- A swirl of peanut butter
- Crushed Oreo cookies
- Chopped candy bars, like Reese's cups, Twix, or Snickers
- Peanut butter chips
- Rainbow sprinkles on top
Cast Iron Walnut Brownies
- ½ cup (113 g) unsalted butter, melted
- ½ cup (100 g) granulated sugar
- ¾ cup (160 g) light brown sugar
- 2 teaspoons vanilla extract
- 2 large eggs, room temperature
- ¾ cup (90 g) all-purpose flour
- ½ cup (42 g) natural cocoa powder
- ½ teaspoon salt
- ½ cup (90 g) mini chocolate chips
- ½ cup (56 g) walnuts, chopped
- Preheat oven to 350 degrees Fahrenheit. Lightly grease a 10-inch cast iron skillet with butter and set aside.
- In a large mixing bowl, add your melted butter, granulated sugar, brown sugar, and vanilla, stirring to combine. Add eggs and stir until completely incorporated.
- In a separate bowl, sift together your dry ingredients - flour, cocoa, and salt. Slowly stir dry ingredients into wet ingredients until combined. Scrape down the sides of your bowl.
- Stir in chocolate chips and walnuts. Pour into your prepared cast iron pan and use a spatula to spread evenly to the edges. Batter will be thick.
- Bake for about 28-32 minutes, or until brownies are set in the middle. Insert a toothpick into the center of the pan. If toothpick comes out with wet batter, the brownies are not done. Continue checking every 2 minutes. If toothpick comes out clean or with a few crumbs, the brownies are done.
- Allow brownies to cool before slicing and serving.
- Brownies will keep for 4-5 days in a sealed container at room temperature.
- Dutch cocoa can be substituted with natural cocoa powder.
- Walnuts can be omitted or substituted with chopped pecans, almonds, or peanuts.
- Recipe can also be made in an 8x8 or 9x9 square pan - baking times will vary.
- Brownies slice better at room temperature. Slicing warm brownies may cause them to crumble slightly at the edges.