Yield: 9″ lemon blackberry crumb cake // Total Time: 1 hr. 20 min. // Disclaimer: This post includes affiliate links.
Light and buttery vanilla cake, topped with blackberries, lemon curd, and lemon streusel.
Why you’ll love this lemon blackberry crumb cake
1. The cake is light, buttery & moist. The base for this cake is the same as my chai apple crumb cake and cranberry almond crumb cake. It’s light and moist & a fork cuts through it so easily.
2. It’s the perfect summer flavor combo. Blackberries and lemon are probably my favorite fruit combo. They’re also super reminiscent of summer, making this cake perfect for summer or if you need a pick-me-up in the cold winter months. The lemon curd & blackberries meld into a lemon curd blackberry jam while baking which is also just *so* good.
3. It’s loaded with streusel. Streusel is NEVER optional on this blog, that’s why this cake is loaded with a lemon brown sugar streusel.
Lemon blackberry crumb cake recipe tips
Weigh your ingredients
- Weighing your ingredients is important for getting the recipe perfect and getting consistent results. Not weighing your ingredients can lead to adding too much or too little of an ingredient which can lead to the recipe not turning out properly. If you haven’t already, I highly recommend purchasing a kitchen scale. This one is super cheap and worked well for me when I was starting out!
Mix the batter carefully
- It is super important to not overmix the cake batter or you end up with a tough and chewy cake rather than a light and moist cake. When alternating between adding the wet and dry ingredients, be sure to only mix just until the ingredient is fully combined and no more.
Room temperature ingredients
- It is important for the ingredients to be at room temperature so that they properly incorporate with each other. Take out the egg, butter, and buttermilk at least 30 minutes and up to 1 hr 30 min. before starting the recipe. To bring an egg to room temperature quickly, you can place it under hot water for 1 minute. To bring butter to room temperature quickly, slice it, place it on a plate, and microwave it in 5-second intervals. For buttermilk, you can also microwave it in 5-second intervals until it’s no longer cold (but not hot!)
Keep an eye on the cake!
- Baked goods love to go from underbaked to overbaked in what seems like a split second. Start checking at the cake with a toothpick around 40 minutes. The cake is done when only a few moist crumbs stick to the toothpick.
Ingredients and substitutions
For the lemon streusel:
Unsalted butter: the base of the streusel, really what makes it buttery and delicious. You can use salted butter here as well!
Light brown sugar: sweetens and adds flavor to the streusel. In a pinch granulated sugar will work here as well.
All purpose flour: adds structure to the streusel.
Lemon zest: for flavor!
For the butter cake:
All purpose flour: the structure of the cake. I would not recommend using cake flour as the cake is already super fluffy and tender using the all purpose.
Baking powder: for helping the cake rise.
Salt: for balancing and bringing out the sweetness of the cake.
Unsalted butter: for tenderizing the cake and giving it that classic buttery taste. You can substitute in salted butter, just omit the extra salt from the recipe.
Granulated sugar: for sweetening the cake and keeping it moist. The sugar also helps aerate the butter to give this cake it’s rise and keep it light and fluffy.
Eggs: for moisture, structure, and binding the batter together.
Vanilla: I use and love this vanilla extract.
Buttermilk: for tenderizing the cake and adding moisture. I highly recommend using buttermilk but I know it can be hard or annoying to purchase, especially if you don’t plan on using it for anything else. If you’re looking for an easy substitute for this recipe, combine 50g of sour cream with 100g of milk and use as normal.
For the filling:
Blackberries: for flavor. I recommend blackberries because I love the flavor combo, but this cake would be delicious with raspberries, blueberries, or even a combination of all three! I wouldn’t recommend using frozen berries here because they would be too watery.
Lemon curd: you can either use homemade or store-bought.
How to make lemon blackberry crumb cake
1. Prep. If you want to make your own lemon curd, you’ll want to make it before starting the cake. At this point, you’ll also want to slice the blackberries in half so that they’re ready to go later!
2. Make the streusel. In a medium sized bowl, melt the butter. Add in the flour, sugar, and lemon zest. Use a fork to mix the ingredients together until you have formed little clumps of dough.
3. Cream the butter and sugar. In a medium sized mixing bowl or in the bowl of a stand mixer, cream together the butter and sugar on medium-high speed until light and fluffy, 3-4 minutes. Beat in the eggs and vanilla until well combined.
4. Alternate wet and dry ingredients. Add half of the dry ingredients to the batter, and mix just until no flour streaks remain. Then, add in all of the buttermilk, then mix until combined. Add in the remaining flour, gently stirring just until no flour streaks remain.
5. Bake. Pour the batter into a prepared cake pan, smoothing off the top. Gently place the blackberries on top, followed by the lemon curd. Top the cake off with the streusel, then bake for 40-50 minutes, until a toothpick inserted in the center of the cake comes out clean.
6. Serve and enjoy! Let the cake come to room temperature, then slice, serve & enjoy!
Homemade lemon curd
If you’re interested in making your own lemon curd, you can check out my recipe here! The recipe makes quite a large batch but can either be scaled down (x.33), or be stored in the fridge/freezer for other bakes!
Lemon blackberry crumb cake Q & A
Can I double this recipe?
Definitely! Simply double all of the ingredients in this crumb cake then split evenly between two 9″ cake pans.
How to store lemon blackberry crumb cake
Like most baked goods, this cake will taste best served on the day it is baked. However, it can be stored in an airtight container at room temperature for up to 3 days.
Why do you measure in grams?
My recipes are all written in grams because it is the most accurate way to bake. When you use a kitchen scale, you ensure that your baked goods turn out as close to the written recipe as possible. Plus, the cleanup is way easier when using a scale! I will provide standard cup measurements but please note that I have not tested the recipe using cup measurements and therefore can not guarantee your recipe will come out how mine did. Here is my favorite kitchen scale, and here’s an article about why I use a kitchen scale, and why you should too!
A note on oven temperature
Ovens vary and fluctuate in temperature. For example, I always have to set my oven to 330°F if I want it to bake at 350°F. If you love to bake like I do, I highly recommend getting an oven thermometer. They are super helpful for letting you know when your oven might be lying to you! I use this one.
Tools and ingredients
You can find all my favorite tools and ingredients that I use on my Amazon Storefront page, here!
Did you make this lemon blackberry crumb cake?
If you made this lemon blackberry crumb cake I would love to see it and know your thoughts! Please leave a comment and review down below, and tag me on Instagram @freshbeanbakery. If you have any questions about the recipe I will gladly do my best to answer them in the comments below!
Lemon Blackberry Crumb Cake
- 60 g unsalted butter (¼ c.)
- 90 g light brown sugar (⅓ c. + 1 tbsp.)
- 120 g all purpose flour
- 1 tbsp. lemon zest (~1 small lemon)
- 190 g all purpose flour (1 ½ c. + 1 tbsp.)
- 2 tsp. baking powder
- ½ tsp. salt
- 125 g unsalted butter (½ c. + 1 tbsp.) room temperature
- 170 g granulated sugar (¾ c. + 2 tbsp.)
- 2 eggs room temperature
- 1 tsp. vanilla
- 150 g buttermilk (⅔ c.) room temperature
- 170 g blackberries (1 c.) cut in half
- 225 g lemon curd* (1 c.)
- Prep: if you are making homemade lemon curd, make it before starting the cake. Also, cut the blackberries in half lengthwise and set them aside.
- Preheat the oven to 350°F / 175°C. Generously butter a 9" cake pan. Crumple up some parchment paper, then un-crumple it and place it into the buttered cake pan, making sure it sticks to the bottom and sides. Set aside.
- In a medium sized bowl, melt the butter. To the butter, add the sugar, flour, and lemon zest. Use a fork to mix the ingredients together until you have formed clumps of dough. Set aside.
- In a small bowl, whisk together the flour, baking powder, and salt. Set aside.
- In the bowl of a stand mixer fitted with the paddle attachment (or with a hand mixer, in a large bowl) beat together the butter and sugar for 3-4 minutes, until light and fluffy.
- Use a rubber spatula to scrape down the sides of the bowl. Add in both eggs and the vanilla. Beat until well combined (~1 min.)
- Add in half of the flour mixture, and mix by hand just until the flour is incorporated. Add in all of the buttermilk and mix until combined. Add in the rest of the flour, and lightly fold the mixture together just until all of the flour is incorporated.
- Pour the cake batter into the prepared cake pan, smoothing out the top. Gently place the halved blackberries in an even layer over the cake, followed by the lemon curd. Top it all off with the lemon streusel.
- Bake for 40-50 minutes, until a toothpick inserted in the center of the cake comes out clean or with only a few moist crumbs. Let the cake cool in the pan until it's no longer too hot to touch, then use the parchment to lift the cake out of the pan.
- Let the cake come to room temperature, then serve and enjoy!