Name: Easy Homemade Brownie Mix in a Jar
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Ingredients: 1 cup all-purpose flour (120g); 1 cup unsweetened cocoa powder (85g); 1½ cups sugar (either 1½ cups granulated, or 1 cup packed brown sugar plus ½ cup granulated); 1 tsp baking powder; 1 tsp salt; 1 cup mix-ins (chocolate chips, chopped walnuts or pecans, or a combination); 1 cup (2 sticks) unsalted butter, melted (or 1 cup neutral oil); 3 large eggs; 1 tsp vanilla extract

I keep a quart jar of homemade brownie mix on the second shelf of my pantry, right next to the vanilla, and it has saved me more times than I can count.

My kids have a way of announcing they need a treat for school the night before. With this jar, a pan of brownies is twenty minutes of actual work, no box needed, no last-minute grocery run.

The ratios here are the ones that matter: 1 cup of cocoa to only 1 cup of flour. That low flour ratio is doing the fudgy work, and I’d resist any urge to even them out.

You can also make several jars at once and give them as gifts. Just tape the baking instructions to the lid, because a jar without the wet ingredient amounts is just a pretty paperweight.

Prep: 10 minutes · Cook: 30 minutes · Total: about 1 hour (with cooling) · Serves: 12

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How do you make homemade brownie mix in a jar?

Layer the dry ingredients into a quart jar without shaking them together: flour first, then cocoa, sugar, baking powder, salt, and mix-ins on top. At baking time, stir in 1 cup melted butter, 3 eggs, and 1 tsp vanilla, then bake at 350°F for 25 to 30 minutes. Start checking at 25, since the line between fudgy and dry is about three minutes wide.

Why This Recipe Works

Melted butter, not softened, is what makes brownies dense and fudgy. Softened butter traps air when creamed, which lifts the crumb and makes it cakey. Melted butter skips that step entirely.
The 1-cup cocoa to 1-cup flour ratio keeps the batter heavy with chocolate and low in structure, which is exactly what produces a fudgy, dense slab rather than a fluffy cake.
Layering the dry ingredients without mixing preserves the visible bands in the jar. One shake and it all turns brown powder, which ruins the gift presentation and makes it harder to verify what went in.

I made the mistake of shaking my first test jar “just to settle it” and immediately regretted it. The bands are the whole point, and they stay put as long as you spoon each layer in gently.

What Makes This Homemade Brownie Mix Special

Brownies are twenty minutes of active work when the dry mix is already done.
Every ingredient comes from a normal supermarket pantry, nothing specialty.
It makes a great gift, and it’s one you’d actually want to receive yourself.
One batch of jars covers multiple gifts at once, so it scales up easily.

What Goes Into Homemade Brownie Mix

1 cup all-purpose flour (120g)
1 cup unsweetened cocoa powder (85g)
1½ cups sugar (either 1½ cups granulated, or 1 cup packed brown sugar plus ½ cup granulated)
1 tsp baking powder
1 tsp salt
1 cup mix-ins (chocolate chips, chopped walnuts or pecans, or a combination)
1 cup (2 sticks) unsalted butter, melted (or 1 cup neutral oil)
3 large eggs
1 tsp vanilla extract

Ingredient Notes

The sugar choice is a real decision. Brown sugar is hygroscopic, meaning it holds onto moisture, so the version made with 1 cup packed brown sugar plus ½ cup granulated bakes up chewier and stays soft longer.

All granulated sugar gives you a crisper, slightly crackly top. Neither is wrong, they’re just different brownies.

For the fat, Cooking With Carlee confirms both melted butter and oil work at the same 1-cup measure. Butter brings more flavor.

Oil produces a slightly softer crumb that holds its texture a day or two longer. I use butter when I’m baking for the table and oil when I’m gifting the jar, since the recipient might not bake it right away.

Cocoa powder matters here more than in most recipes, because it’s carrying the whole flavor load. Standard unsweetened cocoa from any grocery store works fine.

Dutch-process cocoa will give you a darker, milder brownie, but don’t use it if you’re also using baking powder, since the two don’t react well together.

Let’s Make It

Set up your jar. Place a clean, dry quart-sized mason jar on the counter. Make sure it’s completely dry inside, even a few drops of moisture will cause the dry mix to clump over time.
Add the flour. Spoon 1 cup of all-purpose flour into the bottom of the jar, pressing it gently into an even layer. This is the foundation layer, and it goes in first so the heavier mix-ins don’t crush it.
Add the cocoa. Spoon 1 cup of unsweetened cocoa powder directly on top of the flour in a smooth, even layer. Don’t tap or shake the jar, the bands should stay distinct and visible through the glass.
Add the sugar. Spoon in your sugar choice (either 1½ cups granulated, or 1 cup packed brown plus ½ cup granulated) on top of the cocoa. Brown sugar packs down more than granulated, so press it in firmly so it sits level.
Add the baking powder and salt. Spoon 1 tsp baking powder and 1 tsp salt directly onto the sugar layer. They’re small amounts, so just scatter them evenly across the surface before adding the next layer.
Add the mix-ins last. Pour 1 cup of chocolate chips, chopped nuts, or a combination on top. These sit at the very top of the jar where they’re visible and where they won’t sift down through the finer powders during storage. Seal the jar tightly.
When ready to bake, preheat the oven. Set the oven to 350°F and get out a 9×13-inch baking pan. Pour the entire contents of the jar into a large mixing bowl and stir the dry ingredients together until evenly combined.
Add the wet ingredients. Add 1 cup melted butter (or oil), 3 large eggs, and 1 tsp vanilla extract to the bowl. Stir until just combined and no dry streaks remain. The batter will be thick and glossy.
Bake the brownies. Spread the batter evenly into the prepared pan. Bake at 350°F for 25 to 30 minutes. Neither of the recipes I worked from gives a doneness cue, which is the hard part with brownies, so here is what I go by in my own kitchen: I start checking at 25 minutes and pull the pan while the center still looks slightly underdone. Waiting until it looks fully set has given me dry brownies every time.
Cool before cutting. Let the pan cool on a wire rack until it is no longer warm to the touch before cutting. The brownies firm up as they cool, and cutting too early gives you crumbled edges instead of clean squares.

Good to Know

Don’t shake or tap the jar after layering. The visible bands are the whole visual appeal of a gift jar, and one good shake collapses them into a uniform brown powder.
Mainly Homemade notes the dry mix keeps for about a month in a jar at room temperature. Label the jar with the date so you don’t lose track.
Always attach the baking instructions to the jar when gifting. The wet ingredients (butter, eggs, vanilla) and the oven temperature aren’t obvious, and a jar without them is genuinely useless.
The recipes I worked from stop at the time and give no doneness cue, so trust your own eye here. I overbaked my first batch waiting for the center to look done, and they were dry all the way through.
If you use brown sugar in the mix, pack it firmly when layering or it’ll leave an air gap that makes the jar look only half full.

Make-Ahead and Leftovers

The dry mix jar keeps at room temperature for about a month, according to Mainly Homemade. That figure comes from one source, so treat it as a guide.

Store it somewhere cool and dry, away from the stove, and keep the lid on. Moisture is the only real enemy here.

Once baked, keep the brownies in an airtight container at room temperature. They taste better on day two once they have had time to settle.

Baked brownies freeze too. Cut them into squares and wrap each one individually before freezing, then thaw at room temperature or pull one out the night before.

What to Serve With Homemade Brownie Mix

A scoop of vanilla ice cream on top is the obvious move, and it works because the cold cream against the warm brownie is a real contrast in both temperature and texture.
A glass of cold milk is what my kids always reach for, and it cuts through the richness without competing with the chocolate.
Whipped cream keeps it lighter than ice cream if you’re serving these after a big dinner and want something less heavy.
A drizzle of caramel sauce pairs well with the nut version, since the salt in the brownie makes the caramel taste more complex.

Equipment Worth Having

A quart-sized wide-mouth mason jar, wide-mouth makes spooning in the layers much easier than a standard-mouth jar.
A large mixing bowl for combining the dry mix with the wet ingredients at baking time, big enough that you can stir without flour flying out.
A 9×13-inch metal or glass baking pan, metal conducts heat more evenly and gives you a slightly crispier edge.
A rubber spatula for spreading the thick batter into an even layer in the pan.
A wire cooling rack so the bottom of the pan doesn’t trap steam and make the brownies soggy underneath.

Common Questions

Can I double the homemade brownie mix and make two jars at once? Yes, just double every dry ingredient and divide evenly between two quart jars. Each jar still bakes with the same wet ingredient amounts (1 cup butter, 3 eggs, 1 tsp vanilla) in a 9×13-inch pan.

What if I don’t have a quart jar? The dry mix fills a standard quart jar snugly. If you only have pint jars, you’ll need to split the mix-ins into a separate small bag and tape it to the jar, since the dry ingredients alone take up most of the space.

Can I use Dutch-process cocoa in this homemade brownie mix? Standard unsweetened cocoa is the better choice here because the recipe includes baking powder. Dutch-process cocoa has been treated with an alkali and doesn’t react well with baking powder, which can affect how the brownies rise.

How do I know when the brownies are done? Honestly, neither recipe I worked from gives a cue for this, and that is the trickiest part of brownies. What works for me is checking at 25 minutes and pulling the pan while the center still looks a touch underdone, because they keep setting in the hot pan.

Can I add other mix-ins besides chocolate chips and nuts? Absolutely. Peanut butter chips, toffee bits, or dried cherries all work well. Just keep the total mix-in amount at 1 cup so the jar fills correctly and the batter ratio stays balanced.

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