Zucchini Spice Bars: 24 Easy Vegan Bars with Spice Frosting
These zucchini spice bars are what I bake every October when one last oversized zucchini is hiding in the crisper drawer. The cake is soft and moist, scented with cinnamon, ginger, nutmeg and a little clove, and it’s finished with a fluffy cinnamon frosting that tastes like the best part of a spice cake. Nobody ever guesses there’s a vegetable in there.
They’re also the most practical dessert I make. One bowl for the dry ingredients, one for the wet, a single 9×13 pan, and you get 24 frosted squares. I take them to potlucks, bake sales and soccer practice, and the pan always comes home empty.
Prep: 20 minutes | Cook: 25 to 30 minutes | Total: 1 hour 50 minutes, including 1 hour cooling | Serves: 24 bars | Diet: vegan, egg-free, dairy-free
Why You’ll Love These Zucchini Spice Bars
- They stay moist for days. Grated zucchini and applesauce keep the crumb tender.
- No eggs, no dairy, no mixer for the batter. Just two bowls and a whisk.
- They feed a crowd. One pan makes 24 generous bars.
- The frosting is easy. Five ingredients, two minutes of beating, done.
- They’re cheap. The whole pan of zucchini spice bars costs about $6.
Ingredients
Everything for these zucchini spice bars is a pantry staple apart from the zucchini itself. A medium-large zucchini, about 10 ounces, gives you the 2 cups you need.
For the Bars
- 2 cups all-purpose flour (250g)
- 1 teaspoon baking soda (6g)
- 1/2 teaspoon baking powder (2g)
- 1/2 teaspoon fine salt (3g)
- 2 teaspoons ground cinnamon (5g)
- 1/2 teaspoon ground ginger (1g)
- 1/4 teaspoon ground nutmeg and 1/4 teaspoon ground cloves (1g)
- 1 cup packed light brown sugar (200g)
- 1/2 cup granulated sugar (100g)
- 1/2 cup neutral oil (120ml)
- 1/2 cup unsweetened applesauce (120g)
- 1/2 cup unsweetened plant milk (120ml)
- 1 tablespoon apple cider vinegar (15ml)
- 2 teaspoons vanilla extract (10ml)
- 2 cups grated zucchini, lightly squeezed, from 1 medium-large zucchini (250g)
- 1/2 cup chopped walnuts, optional (60g)
For the Cinnamon Spice Frosting
- 1/2 cup vegan butter, softened (113g)
- 2 1/2 cups powdered sugar (300g)
- 1 teaspoon ground cinnamon (2.5g)
- 1 teaspoon vanilla extract (5ml)
- 2 to 3 tablespoons plant milk (30-45ml)
Ingredient Notes
Zucchini: No need to peel it. The green flecks look pretty and soften completely in the oven. Very large zucchini can have tough seeds, so scoop those out first.
Spices: If you don’t have every spice, use 1 tablespoon of pumpkin pie spice instead of the cinnamon, ginger, nutmeg and cloves.
Vinegar: It reacts with the baking soda to give the bars lift. You won’t taste it.
How to Make Zucchini Spice Bars
- Prep the Pan. Heat the oven to 350F (175C). Grease a 9×13-inch metal pan and line it with parchment, leaving some overhang.
- Squeeze the Zucchini. Grate the zucchini on the large holes of a box grater. Squeeze it gently in a clean towel to remove some, not all, of the liquid. You want 2 loosely packed cups.
- Whisk the Dry Ingredients. In a large bowl, whisk the flour, baking soda, baking powder, salt, cinnamon, ginger, nutmeg and cloves.
- Mix the Wet Ingredients. In a second bowl, whisk the brown sugar, granulated sugar, oil, applesauce, plant milk, vinegar and vanilla until smooth.
- Combine. Pour the wet mixture into the dry and stir until just combined. Fold in the zucchini and walnuts. The batter will be thick.
- Bake. Spread the batter evenly in the pan and bake 25 to 30 minutes, until the top springs back and a toothpick comes out clean.
- Cool Completely. Cool the bars in the pan on a rack for at least 1 hour. Frosting warm bars makes it slide off.
- Make the Frosting. Beat the vegan butter until creamy, then beat in the powdered sugar, cinnamon and vanilla. Add plant milk a tablespoon at a time until fluffy and spreadable.
- Frost and Slice. Spread the frosting over the cooled bars, dust with a pinch of cinnamon and cut into 24 squares.
Tips for the Best Zucchini Spice Bars
Squeeze lightly. This is the big one. Wring out too much liquid and the bars bake up dry. Skip squeezing and they turn gummy. A gentle squeeze over the sink until it stops dripping heavily is perfect.
Use a metal pan. Metal bakes the bars evenly. Glass pans take about 5 minutes longer and can brown the edges more.
Don’t overmix. Stir until you can’t see dry flour, then stop. Overmixing makes the bars dense.
Cool before frosting. Frosting warm zucchini spice bars turns the topping into a glaze that slides off. Give them a full hour.
Chill for clean cuts. Ten minutes in the fridge after frosting helps you cut neat squares. Wipe the knife between cuts.
Why Zucchini Works in Dessert
Zucchini is about 95 percent water and has a very mild flavor, which makes it a great baking ingredient. As the bars bake, the shreds release moisture slowly into the crumb, so the cake stays soft for days without extra oil or eggs. The spices and brown sugar take over the flavor, and the zucchini just quietly does its job.
It’s also a smart way to stretch a budget. A single zucchini that would cost the same as a small bag of chocolate chips adds bulk and moisture to a whole pan of dessert. If your garden or a generous neighbor overloads you, grate and freeze it in 2-cup portions so you can bake zucchini spice bars all winter. The National Center for Home Food Preservation has clear freezing guidelines if you want to stock up.
Thawed frozen zucchini releases more liquid than fresh, so squeeze it a little more firmly before measuring.
Variations and Swaps
- Chocolate chip: Swap the walnuts for 1/2 cup dairy-free chocolate chips.
- Cream cheese style frosting: Replace half the vegan butter with vegan cream cheese for a tangier topping.
- Raisin spice: Fold in 1/2 cup raisins soaked in hot water for 10 minutes.
- Unfrosted snack bars: Skip the frosting and sprinkle the batter with cinnamon sugar before baking.
- Half whole wheat: Swap 1 cup of the flour for white whole wheat flour.
Make Them Ahead for a Crowd
Zucchini spice bars are a great make-ahead dessert. Bake the bars up to two days before your event, let them cool completely, then wrap the pan tightly and leave them at room temperature. Make the frosting the morning you plan to serve and spread it on a couple of hours ahead so it has time to firm up.
If you’re driving them somewhere, keep the bars in the pan and cut them on site. They travel better that way, and the frosting stays smooth. For a bake sale, cut the bars, chill them for 20 minutes and wrap each square in parchment or a small bag.
What They Cost
My rough breakdown: zucchini $1.00, flour $0.45, sugars $1.00, oil $0.50, applesauce and milk $0.45, vegan butter $1.40, powdered sugar $0.80, and spices, vinegar and vanilla about $0.50. That’s around $6 for 24 zucchini spice bars, so about 25 cents a square.
Serving Ideas
These are perfect with afternoon coffee or tea, or packed into lunchboxes. For a fall dessert spread, set them out with a warm spiced pear crisp and a basket of vegan pumpkin chocolate chip muffins.
Storage
Fridge: Because of the frosting, store frosted zucchini spice bars covered in the fridge for up to 4 days. Let them sit out 15 minutes before serving.
Freezer: Freeze unfrosted bars, wrapped well, for up to 3 months. Thaw at room temperature, then frost.
Frequently Asked Questions
Can I taste the zucchini in zucchini spice bars?
No. The zucchini melts into the crumb and the spices take center stage. You’ll only see a few green flecks.
Can I make these in a different pan?
Yes. A 9×9 pan works for half the recipe, baked for 22 to 26 minutes. A half sheet pan works for a double batch, baked for about 25 minutes.
Do I need to peel the zucchini?
No. The skin softens completely. Just wash it and trim the ends.
Can I make the bars without oil?
You can replace the oil with more applesauce, but the bars will be denser and more cakey-chewy. I like a mix of half oil and half applesauce as written.
How do I know when they’re done?
The center should spring back when pressed and a toothpick should come out clean or with a few dry crumbs.
Bake a Pan This Week
These zucchini spice bars are cozy, simple and a little sneaky in the best way. They turn one humble zucchini into a pan of frosted squares that feeds a crowd for pocket change. For more sweet ideas, browse my vegan dessert recipes.
If these bars disappeared at your house too, share the recipe with a friend who has too much zucchini, and follow me on Pinterest for more vegan fall desserts on a budget. When you bake them, rate them in the recipe card below and tell me in the comments if you added walnuts or chocolate chips. Happy baking!
