These Sourdough Discard Halloween Kitchen Sink Cookie Bars are great to make while you have Halloween candy on hand! Combine M&M's, pretzels, Halloween sprinkles, and chocolate chips to make a salty-sweet cookie treat. The best part? Use whatever you have on hand! Have Reese's pieces? Or want to use leftover chocolate candies? Go for it!
Why you'll love this recipe
- Cookie bars are easy to make. Bake them all in one go - no need to do mutliple batches of cookies!
- Interested in a classic cookie bar? Try these Sourdough Discard Chocolate Chip Cookie Bars.
- This recipe uses sourdough discard, but you could easily modify to use active sourdough starter if you prefer.
- You can use whatever add-ins you have on hand! Use M&Ms, Reese's pieces, chunks of chocolate candy, different sprinkles, and more! It's a great way to use up leftover Halloween candy, too.
- These cookie bars freeze well, so if you have any left over, pop them in the freezer to enjoy later!
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Ingredients
There are only a few key things you'll need to bring this recipe together.
- Sourdough discard: The sourdough discard should be unfed and at room temperature for this recipe. This recipe is designed for a sourdough starter that uses a 1:1 ratio (when you feed your starter, it's with 1 part flour and 1 part water). If your starter uses a different ratio, you may need to adjust some of the ingredients in this recipe.
- Learn more about how to make a sourdough starter.
- M&Ms: Lots of flexibility here! You can use any kind of M&Ms (classic, minis), or other chocolate candies like Reese's pieces.
- Chocolate chips: I like to use dark chocolcate chips, but any kind of chocolate will work. You can also use chocolate chunks, if you prefer
- You might like these Sourdough Discard Chocolate Chip Cookies, too!
- Pretzels: Any kind is fine! They will get crushed a bit as they're mixed into the batter, so the shape is not important.
See full recipe below for detailed directions.
Substitutions & Variations
This is a very adaptable recipe and below are a few easy substitutions and variations you can try.
- Use active sourdough starter - While it's not needed for leavening purposes, if you'd like to use active sourdough starter instead of discard, you can. To do so, replace the sourdough discard with active starter (200g). You don't need to change any other ingredients in the recipe.
- Use different chocolate - I use dark chocolate in the recipe, but this will work with any kind of chocolate.
- Use different candies - Try Reese's pieces, or cut up chocolate candy bars.
- The googly-eye sprinkles are what make these fun for Halloween, but you could easily make this with other festive sprinkles for other occassions!
How to Make Sourdough Discard Halloween Kitchen Sink Cookie Bars
There are just a few easy steps to bring these cookie bars together! The full recipe with detailed directions is at the bottom of this post.
- Step 1: Combine dry ingredients in a mixing bowl. Set aside.
- Step 2: Cream together the butter and sugars until light and fluffy.
- Step 3: Add the dry ingredients into the creamed butter mixture. Mix until combined.
- Step 4: Add the mix-ins (pretzels, M&Ms, chocolate chips, and sprinkles). Stir until combined.
- Step 5: Spread the cookie dough into a 9x13-inch baking pan (using a cookie scoop is a good way to start!). Top with additional pretzels, M&Ms and sprinkles.
- Step 6: Bake for 35-40 minutes, then let the cookie bars cool in the pan for at least 30 minutes. Transfer to a tray or cutting board, slice and serve!
Expert Baking Tips
- The pretzels will be crushed as you're mixing the dough, so the shape of the pretzel doesn't matter. And no need to pre-crush them!
- The cookie dough is going to be a bit sticky, and that's ok. Spread it as evenly as you can in the baking pan, but no need to stress - it's going to rise and spread more as it bakes, smoothing out any rough spots.
- You can top the cookie bars with additional pretzels, sprinkles or candy. This is purely for aesthetics!
- The googly-eye sprinkles are what make these fitting for Halloween, but you can use other candy or sprinkles for other uses!
- Looking for other Halloween treats? Try these Chocolate Covered OREOs with Halloween sprinkles!
Storage
Room Temperature Storage: Store cookie bars in an airtight bag or container at room temperature for up to two weeks. They will get a bit harder and crispier as they sit, but they will still be delicious!
Freezer Storage: You can also freeze these cookie bars in an airtight bag or container for up to three months. Make sure the cookies are fully cooled before you package them for freezing. When ready to eat, let them thaw to room temperature.
Recipe FAQs
This is optional. It's easier to remove the cookie bars if you use the parchment paper, but it's harder to spread the cookie dough, so it's a bit of a toss up!
Let them cool in the pan for 30-60 minutes. This will make it easier to remove them, and will also give you a cleaner cut when you slice them.
More Sourdough Discard Cookie Recipes
If you tried these Sourdough Discard Halloween Kitchen Sink Cookie Bars or any other recipe on my website, please leave a ⭐ star rating and let me know how it went in the comments below. I'd love to hear from you! Happy Baking!
Sourdough Discard Halloween Kitchen Sink Cookie Bars
Ingredients
- 2 ¼ cups + 2 Tablespoons all-purpose flour
- 1 teaspoon kosher salt
- 1 teaspoon baking soda
- 1 ½ teaspoons cornstarch
- ½ teaspoon baking powder
- ½ cup unsalted butter softened
- 1 ¼ cup brown sugar packed
- ½ cup granulated sugar
- 1 egg
- 2 teaspoons vanilla extract
- 200 grams (about ¾ cup) sourdough discard unfed, at room temperature
- 6 ounces chocolate chips
- 6 ounces M&Ms plus more for topping
- 1 cup pretzels plus more for topping
- 2 Tablespoons Halloween sprinkles
Instructions
- Preheat the oven to 350℉ (175℃) and line a 9x13-inch baking pan with parchment paper (this is optional, but makes it easier to remove the cookie bars after baking). Set aside.
- In a medium bowl, whisk together flour, salt, baking soda, cornstarch, and baking powder. Set aside.
- In the bowl of a stand mixer fitted with a paddle attachment (or in a large mixing bowl with a hand-held mixer), cream the butter and sugars until light and fluffy, 2-3 minutes.
- Add the egg, vanilla extract, and sourdough discard and mix on low until smooth and combined.
- Add the flour mixture and mix on low until combined. Stir in the chocolate chips, M&Ms, pretzels, and sprinkles until combined.
- Using a large cookie scoop or spoon, roughly scoop the cookie dough into the prepared 9x13-inch baking pan. Use your hands or a spatula to evenly press the cookie dough to the edges of the pan and fill any spaces.This doesn't need to be too precise - the dough will rise and spread as it bakes, filling in any small gaps or rough spots!
- Optional: Sprinkle extra M&Ms and crushed pretzels on top of the dough. If using Halloween googly eyes, lightly press those into the top of the dough.
- Bake for 35-40 minutes until browned and the cookie bars are set on the edges. Let cool in the baking pan for at least 30 minutes before transferring to a cooling rack to cool fully. Slice into bars, then serve!Pro tip: Before serving, add a few more googly eyes! They tend to melt during baking, so add more after baking!
Jessica Vogl says
So fun and so easy! Love the salty-sweet combination, and the googly eyes!