These muffins are fluffy, rich, and full of chocolate and zucchini! They have a delicious buttery streusel sprinkled on top before baking.

These muffins are really soft and fluffy. I was amazed how you can’t taste the zucchini at all! The chocolate really overpowers it.
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.
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Ingredients Notes
Scroll through this section to view certain key ingredients we’re using in these muffins! For the full recipe with measurements, keep scrolling.
- Butter - This will be cold and for the streusel.
- Cocoa powder – Make sure to use a natural unsweetened cocoa powder like Hershey’s.
- Eggs – Make sure they’re at room temperature before beginning.
- Flour – All-purpose flour is used in this recipe. Don't use any other flour.
- 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 – Always make sure to use a good quality vanilla.
- Zucchini – Adds flavourless moisture into the muffins. Shred coarsely using a grater. If there is a lot of moisture coming from it after shredding, gently blot with a paper towel. They shouldn't be super wet when adding into the batter (dripping).
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 tin with 12 liners and set aside. If you need a recommendation, this is my favourite tin. Shred the zucchini with a grater on the coarse side 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. With your hands, combine it all together until crumbly and a streusel forms. Set in the fridge while you make the muffin batter.
Step 3 – Mix dry ingredients. In a large bowl, add in the sifted dry ingredients; 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, 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, fold to create a soft muffin batter. Mix until just combined, don't over-mix!
Step 6 – Mix in add-ins. Add the shredded zucchini and mini chocolate chips and mix in a few times until evenly distributed. Do not over-mix!!
Step 7 – Scoop. Evenly divide the batter between 12 liners. Sprinkle a handful of streusel on top.
Step 8 – Bake. Bake the muffins at 375°F for 20-25 minutes. Mine took 23 minutes total. The muffins are ready when a toothpick inserted comes out clean.
These delicious muffins stay fresh at room temperature for a couple of days, and in the refrigerator in an airtight container for up to 7 days!
Expert Baking Tips
Here are a few expert baking tips from my kitchen to yours
- Use a gram scale. It is the most accurate way of measuring your ingredients in the kitchen to prevent mistakes from happening. This is one of my favourites.
- Do not over-mix! A big reason muffins don’t work is because the batter gets over-mixed. Once you see no flour streaks, don't mix anymore.
- 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. Use a gram scale to measure out the dry ingredients to prevent any measuring mistakes.
What do I do with leftover streusel?
Streusel freezes very well! Just place any leftovers you may have in a ziplock bag and stick it in the freezer. You do not need to thaw it to use it, once you are ready to use it, just 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 all-purpose flour
- 1 1/3 cups white sugar
- 1/2 cup unsweetened cocoa powder
- 1 tsp baking soda
- 1 1/2 tsp baking powder
- 1/4 tsp salt
- 2/3 cups oil
- 3 large eggs room temperature
- 2 tsps vanilla
- 1 cup full-fat sour cream room temperature
- 2/3 cups mini chocolate chips
- 1 1/2 cups zucchini grated, about 170g
Instructions
- Preheat the oven to 375℉. Line the muffin tin with 12 liners and set aside. Shred the zucchini with a grater on the coarse side and set aside.1 1/2 cups zucchini
For the streusel
- 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
For the muffins
- In a large bowl, add in the sifted flour, baking soda, white sugar, cocoa powder, salt, and baking powder. Mix together and set aside.2 cups all-purpose flour, 1 1/3 cups white sugar, 1/2 cup unsweetened cocoa powder, 1 tsp baking soda, 1 1/2 tsp baking powder, 1/4 tsp salt
- Into a large bowl add oil, eggs, vanilla, and sour cream. Whisk until well combined.2/3 cups oil, 3 large eggs, 2 tsps vanilla, 1 cup full-fat 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. Don't over-mix!1 1/2 cups zucchini, 2/3 cups mini chocolate chips
- Evenly divide the batter between 12 liners. Sprinkle a handful of streusel on top.
- Bake the muffins at 375°F for 20-25 minutes. The muffins are ready when a toothpick inserted comes out clean with no wet muffin batter.
- Serve them warm, or wait for them to completely cool, and enjoy!
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