These brownies in a jar are individual desserts baked in mason jars—perfect for parties, lunchboxes or holiday gifting. Just add ice cream for an easy, crowd-pleasing treat!
I originally shared this recipe way back in 2011, and it’s still one of my favorite little dessert tricks.
Table of Contents
Baked, Not Layered: Why These Brownies in a Jar Are Different
Unlike most “brownies in a jar” recipes that layer dry ingredients for gifting, this recipe actually bakes the brownies right in the jars! The result? Fudgy, crackly-topped brownies with a portable, ready-to-eat presentation that feels downright celebratory.
All you need is your favorite brownie batter (I use this cocoa powder brownies recipe, but a boxed mix works great, too!), a few canning jars, and a little butter for greasing. Bake, cool slightly and top with a scoop of vanilla ice cream for the ultimate single-serve treat. They’re fun for birthdays, bake sales or edible gifts any time of year.
- Preheat and prep. Preheat your oven to 350ºF. Thoroughly grease the inside of four clean canning jars with butter and set them aside on a baking sheet.
- Fill the jars. Prepare your brownie batter per the recipe or box instructions. Pour the batter into the greased jars, filling each one no more than ¼ full (they rise quite a bit!). Tap the jars gently on the counter to release any air bubbles.
- Bake. Bake the jars on the baking sheet for 40 to 45 minutes, or until a toothpick inserted into the center comes out clean. The tops will puff up and crack slightly like classic brownies.
- Serve and enjoy. Let the jars cool slightly before serving. Top with a scoop of vanilla ice cream or your favorite toppings—whipped cream, butterscotch sauce, sprinkles, you name it!
- Grease your jars really well. You want the brownies to release easily from the jars.
- Don’t overfill the jars. Only fill the jars ¼ full to prevent overflow as they bake.
- Use 4-ounce, wide-mouth jars. They’re easier to fill, eat from and clean.
Storage Instructions
The brownies can be covered and stored at room temperature for up to 2 days or refrigerated for 4 to 5 days.
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Equipment
- 4 4 oz. mason jars
Ingredients
- Butter, for greasing jars
- Your favorite brownie mix, homemade or a boxed mix
- Vanilla ice cream, optional
Instructions
- Preheat the oven to 350ºF.
- Thoroughly grease the inside of four clean canning jars with butter. Set aside.
- Prepare the brownie batter per your recipe’s instructions.
- Pour the batter into each of the greased jars, filling them one-fourth full. Tap the jars lightly on the counter to release any air bubbles. Place the filled jars on a cookie sheet, arranged so that they are not touching each other.
- Bake the jars for 40 to 45 minutes, or until a toothpick inserted comes out clean.
- Top with a scoop of vanilla ice cream.
Kelly’s Notes
- The brownies can be covered and stored at room temperature for up to 2 days or refrigerated for 4 to 5 days.
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Would I be able to heat these in the microwave? I love my brownies hot when I eat them.
Hi Kas! Newer mason jars will have a microwave-safe symbol on the bottom of them. However, it is important to keep in mind that they will still become very hot to the touch.
Love this!
What size jars did you use ?
Hi Tami – I used a standard 16 ounce mason jar. Enjoy!
I was also wondering this. Did you ever find out or am I going to be left guessing the size and burning the brownies?
Hi Kaleigh – What is your question? I wasn’t sure what you are referring to.
Can you use pint and a half jars or quart?
Yes, but it’ll affect the thickness of the batter so you may have to adjust the bake time.
Hi, i have a lot of gerber jars from my baby.. I was wondering if I could use them.. And also I was worried about the glass to break at that temperature in the oven.. I have never made those of desserts and they look wonderful..
Btw I am from Ecuador, I am following you since yesterday, today I made your chocolate chip cookies recipe with cream cheese with all your tips, the cookies were delicious and perfect shape!! Thank you!!
Hi there! I’m not sure if that would work or if the glass is too thin to withstand the heat. I have never tried this recipe with baby food jars so I can’t say with certainty.
Could you please tell me what size jars you used? Thanks!
I use large mouth pint jars. Easier to get out.
rachel they will be good until the seal unseals itself and the top pops.
if i seal them, how long will they be good???? I’d like to send my husband some. but shipping might take 2 to 3 weeks… please help!!!
I use wide mouth pint jars for my desserts. Easier to get out off. I would think they would last at least a year if you use a hot lid on them.
Thank you so much, this is awesome. I’m going to make some right away for my husband!!!
bingo! we’re so totally thinking alike. I love Ball jars. I have made pate’ in them for appetizer. I use them as water glasses (with sliced cucumber). And I use them for dessert during picnics (see my mango-coconut custard trifle with lime syrup…in a jar: http://bit.ly/k4wH1p)
Such a simple, elegant, and fun entertaining idea! Love the thought of using Mason/Ball jars. They’re relatively inexpensive, and give the recipe a rustic/chic look. Definitely making this recipe @ home!
These look so beautiful! Great idea.
i need to find some jars so i can make these!
and you’re totally onto something with that dessert idea :)
These are soooo adorable. Perfect for a spring dinner party. And it’s even eco-friendly. ;)