Lemon Blackberry Crumb Cake

Yield: 9″ lemon blackberry crumb cake // Total Time: 1 hr. 20 min. // Disclaimer: This post includes affiliate links.

Light, moist vanilla cake topped with lemon curd, fresh blackberries, and 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.

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. In a small batch recipe it is especially important to get those correct measurements because there is less room for error. 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!

line your pan tall with parchment paper!

This cake is not one that you want to flip upside down to get it out of the pan. Butter your pan, and get out a sheet of parchment paper. Crinkle up the parchment paper, then un-crinkle it and place it in your buttered pan, pressing the parchment up the sides of the pan. This will give you a way to lift the cake out of the pan (plus I happen to enjoy the little crinkles it puts in the sides – it’s a little rustic almost!)

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!)

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

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.

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!