These muffins are fluffy, rich, and full of chocolate! They have a delicious buttery streusel sprinkled on top before baking. Start your morning off right with these delicious Chocolate Zucchini Streusel Muffins!

These muffins are soft and fluffy and full of soo much goodness. I was really surprised how chocolate-y they are, you can’t taste the zucchini at all!
It has a simple 3 ingredient buttery streusel sprinkled on top before baking. The streusel crisps up while in the oven and a delicious muffin top is formed.
For more muffin recipes, try Lemon Raspberry Streusel Muffins, Bakery Style Chocolate Chip Muffins, and Peach Streusel Muffins.
Why this recipe works
- Easy to make – Everything gets mixed in just a couple simple steps.
- Delicious – The perfect balance of hearty, sweet, and fluffy!
- No mixer required – Only a bowl, a whisk, and a spatula.
- Zucchini – A great way to use up some zucchini!
Ingredients Notes
Full recipe and ingredients are in the recipe card below. Feel free to scroll through this section to view certain key ingredients we’re using!
Butter - This will be cold and for the streusel.
Cocoa powder – Make sure to use a natural unsweetened cocoa powderlike Hershey’s.
Eggs – Make sure they’re at room temperature before beginning.
Flour – All-purpose flour is used in this recipe.
Mini chocolate chips – Adds some extra chocolate into the muffins! I like using mini chocolate chips for this recipe so there’s pockets of chocolate in every bite, but you can also use semi-sweet chocolate chips.
White sugar – I used granulated white sugar for this recipe. Brings sweetness to the muffins.
Vanilla – Use a good quality vanilla to really enhance the flavours and tie it all together!
Zucchini – Adds flavourless moisture into the muffins that’s really remarkable and magical in the oven! Shred it using a grater. If there is a lot of moisture coming from it after shredding, gently blot with a paper towel.

Step by step instructions
Here is how to make and bake these Chocolate Zucchini Streusel Muffins. You will need a 12 muffin tin, muffin liners, 3 mixing bowls, a spatula, and a whisk.
Step 1 – Prep. Line the muffin liners with 12 liners and set aside. If you need a recommendation, this is my favourite tin. Shred the zucchini with a grater and set aside. Do not blot the zucchini unless an excessive amount of moisture is dripping from it.
Step 2 – Make the streusel. In a medium sized bowl, add flour, sugar, and cold butter. Using your hands, mix this until crumbly and combined. Set aside while you make the muffin batter.
Step 3 – Mix dry ingredients. In a large bowl, add in flour, cocoa powder, sugar, baking soda, baking powder, and salt. Mix together and set aside.
Step 4 – Add wet ingredients. Into the medium bowl add oil, eggs, egg yolk, vanilla, and sour cream. Whisk until well combined.


Step 5 – Add in wet ingredients. Add the wet ingredients into the dry and using a spatula, gently fold to create a soft muffin batter. Mix until there are almost no flour streaks showing.


Step 6 – Add zucchini. Add the shredded zucchini and mini chocolate chips and mix in a few times, with no flour streaks left. Do not over-mix!!


Step 7 – Scoop. Evenly divide the batter between 12 liners, they should be almost or all the way full. Using a cookie scooper helps big time to minimize the mess. Sprinkle streusel on top.


Step 8 – Bake. Bake the muffins at 425°F for 6 minutes. Then turn the oven down and continue baking at 375°F for an additional 10-12 minutes. Mine took 18 minutes total. The muffins are ready when they bounce back at touch or a toothpick inserted comes out clean.
These muffins stay fresh covered at room temperature for a few days, or in the refrigerator in an airtight container for up to 1 week!

Expert Baking Tips
Here are a few expert baking tips from my kitchen to yours
- Use a gram scale. I cannot emphasize this enough! It is the most accurate way of measuring your ingredients in the kitchen. This is one of my favourites.
- Do not over-mix! A big reason muffins don’t rise or turn out tough is because the batter is over-mixed. Once you see no flour streaks, stop mixing.
- You don’t have to peel the zucchini before shredding it.

FAQ
Do I have to add chocolate chips?
No!
Why are my muffins so wet?
Remember that adding zucchini into your bakes is essentially like adding in flavourless moisture. Make sure all of the dry ingredients are measured out properly, I like to use a gram scale for the most accurate measurements.
Can you taste the sour cream?
No! The sour cream adds a tangy flavour to the muffins, which pairs perfectly with the sweet blueberries.
What do I do with leftover streusel?
Streusel freezes great! Just place any leftovers you may have in a ziplock bag and freeze until needed again. You do not need to thaw it to use it, once you are ready to use it, you can sprinkle it frozen on top of the muffins.

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Chocolate Zucchini Streusel Muffins
Ingredients
For the streusel
- 3/4 cup all-purpose flour
- 5 tbsp butter cold
- 1/3 cup white sugar
For the muffins
- 2 cups flour
- 1 1/4 cups white sugar
- 1/2 cup unsweetened cocoa powder
- 1 tsp baking soda
- 2 tsp baking powder
- 1/2 tsp salt
- 2/3 cups oil
- 2 eggs room temperature
- 1 egg yolk room temperature
- 1 tbsp vanilla
- 1 cup sour cream room temperature
- 1/2 cup mini chocolate chips
- 1 1/2 cups zucchini grated, about 170g
Instructions
- Preheat the oven to 425℉. Line the muffin liners with 12 liners and set aside. Shred the zucchini with a grater and set aside.1 1/2 cups zucchini
- In a small bowl, make the streusel. Combine flour, white sugar, and cold cut up butter. Using your hands, mix it together until combined into a crumbly, streusel mixture. Set aside while you make the muffin batter.3/4 cup all-purpose flour, 1/3 cup white sugar, 5 tbsp butter
- In a large bowl, add in flour, baking soda, sugar, cocoa, salt, and baking powder. Mix together and set aside.2 cups flour, 1 1/4 cups white sugar, 1/2 cup unsweetened cocoa powder, 1 tsp baking soda, 2 tsp baking powder, 1/2 tsp salt
- Into the medium bowl add oil, eggs, vanilla, sour cream, and egg yolk. Whisk until well combined.2/3 cups oil, 2 eggs, 1 egg yolk, 1 tbsp vanilla, 1 cup sour cream
- Add the wet ingredients into the dry and using a spatula, gently fold to create a soft muffin batter. Mix until there are almost no flour streaks left.
- Add the shredded zucchini and chocolate chips and mix in a few times. Continue mixing until no flour streaks are left. Do not over-mix!!1 1/2 cups zucchini, 1/2 cup mini chocolate chips
- Evenly divide the batter between 12 liners, they should be almost or all the way full. Using a cookie scooper helps big time to minimize the mess. Sprinkle streusel on top.
- Bake the muffins at 425°F for 6 minutes. Then turn the oven down to 375°F and continue baking for 10-12 minutes. Mine took 18 minutes exactly. The muffins are ready when they bounce back at touch or a toothpick inserted comes out clean.
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