Pistachio Olive Oil Cake: Blackberry Thyme Buttercream Magic

There’s a special kind of magic that happens when you combine the rich, earthy flavor of pistachios with the fruity notes of a good olive oil. It feels fancy, like something you’d order at a charming little bakery, but I promise you, it’s deceptively simple to make right at home. This Pistachio Olive Oil Cake with Blackberry Thyme Buttercream is the kind of dessert that looks like you fussed for hours, but secretly comes together without any complicated steps. It’s perfect for those times when you want to treat yourself and your loved ones to something a little extraordinary, whether it’s a weekend brunch, a birthday celebration, or just a Tuesday that needs a splash of sweetness.

Table of Contents

Table of Contents

Why You’ll Love This Pistachio Olive Oil Cake

• Unbelievably Moist: Thanks to the olive oil, this cake stays incredibly tender and moist for days—no dry, crumbly cake here!
• Elegant & Impressive: The vibrant green specks of pistachio and the gorgeous purple buttercream make it a total showstopper.
• Naturally Dairy-Free Cake: The cake itself uses olive oil instead of butter, making it a great option for those avoiding dairy (the buttercream, of course, is optional!).
• Perfect Make-Ahead Dessert: The flavors actually improve overnight, making it a fantastic choice for stress-free entertaining.

Gathering Your Ingredients

This recipe uses simple, wholesome ingredients that work together to create something truly special. Here’s what you’ll need:

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For the Pistachio Olive Oil Cake:

• 1 ½ cups all-purpose flour
• ½ cup shelled pistachios, finely ground (plus more for garnish)
• 1 tsp baking powder
• ½ tsp baking soda
• ½ tsp salt
• 2 large eggs, at room temperature
• ¾ cup granulated sugar
• ½ cup extra virgin olive oil (use a good, fruity one!)
• ¾ cup buttermilk, at room temperature
• 1 tsp vanilla extract
• ½ tsp almond extract

For the Blackberry Thyme Buttercream:

• ½ cup fresh blackberries (plus a few extra for garnish)
• 2-3 fresh thyme sprigs
• 1 cup unsalted butter, softened
• 3 cups powdered sugar, sifted
• 1 tsp vanilla extract
• Pinch of salt

How to Make Your Pistachio Olive Oil Cake

1. Preheat your oven to 350°F (175°C). Grease and line a 9-inch round cake pan with parchment paper. This little trick ensures your cake will pop out perfectly every time.
2. In a medium bowl, whisk together the flour, ground pistachios, baking powder, baking soda, and salt. This combines your dry ingredients so everything is evenly distributed.
3. In a separate large bowl, vigorously whisk the eggs and granulated sugar for a good minute until they’re pale and slightly thickened. This helps give the cake a lovely structure. Slowly stream in the olive oil while whisking constantly, followed by the buttermilk, vanilla, and almond extract.
4. Gently add the dry ingredients to the wet ingredients and fold with a spatula until just combined. Remember, a few lumps are better than overmixing! Pour the beautiful green-tinged batter into your prepared pan.
5. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool in the pan for 10 minutes before turning it out onto a wire rack to cool completely. Patience is key here—a warm cake and buttercream are not friends!

Crafting the Blackberry Thyme Buttercream

1. First, create a quick compote. In a small saucepan over medium heat, combine the blackberries and thyme sprigs. Cook for 5-7 minutes, mashing the berries with a spoon, until they break down and become jammy. Strain the mixture through a fine-mesh sieve to remove the thyme stems and seeds. Let this vibrant puree cool completely.
2. In a stand mixer fitted with a paddle attachment (or using a hand mixer), beat the softened butter on medium speed until it’s completely smooth and pale, about 3 minutes.
3. With the mixer on low, gradually add the sifted powdered sugar until incorporated. Add the vanilla and salt, then increase the speed to medium-high and beat for another 3 minutes until fluffy and light.
4. Finally, add 2-3 tablespoons of your cooled blackberry puree to the buttercream and beat until fully incorporated and beautifully swirled. Give it a taste—it’s the best part of the job!

Let’s Talk Equipment

You don’t need any fancy gadgets for this recipe. A good set of mixing bowls, a 9-inch round cake pan, a hand or stand mixer for the buttercream, and a spatula for folding are the main players. A fine-mesh sieve is crucial for getting that smooth, seedless blackberry puree for the frosting.

Tips for a Truly Perfect Cake

• Room Temperature is Key: Having your eggs, buttermilk, and butter at room temperature helps everything emulsify beautifully, resulting in a uniform, tender crumb.
• Grind Those Nuts: Make sure to grind your pistachios until they’re a fine meal, but stop before they turn into paste. A small food processor or blender works great for this.
• Don’t Overmix: Once you add the flour, mix until you no longer see dry spots. Overmixing develops gluten and can make the cake tough.
• Cool Completely: I know it’s hard to wait, but slathering buttercream on a warm cake is a one-way ticket to a melted, slippery mess. Let that cake cool!

How to Serve This Stunning Dessert

Once your cake is cooled and frosted, slice yourself a generous piece. The combination of the nutty, moist cake with the slightly tart and herbal buttercream is just incredible. For a real wow factor, garnish with a few extra crushed pistachios, fresh blackberries, and a tiny sprig of thyme. It pairs wonderfully with a cup of coffee for an afternoon treat or can be dressed up as the grand finale for a dinner party. If you’re looking for a lighter pairing, my Summer Berry Spinach Salad makes a fantastic start to the meal.

Your Pistachio Olive Oil Cake Questions, Answered

Can I make this cake ahead of time?

Absolutely! In fact, I recommend it. The cake’s flavor deepens and becomes even more moist if you wrap it tightly and let it sit at room temperature overnight. You can make the blackberry puree ahead of time and store it in the fridge, but wait to make the buttercream the day you plan to serve it for the best texture.

I don’t have buttermilk. What can I use?

No buttermilk? No problem! A great easy substitute is to add 2 teaspoons of white vinegar or lemon juice to a liquid measuring cup, then pour in regular milk (dairy or non-dairy) until it reaches the ¾ cup line. Let it sit for 5-10 minutes until it slightly curdles, and you’re good to go.

How should I store leftovers?

Because of the fresh fruit buttercream, this cake is best stored covered in the refrigerator. Let the slices sit at room temperature for about 20 minutes before serving to take the chill off. The cake will stay delicious for up to 3 days.

Can I use frozen blackberries?

You can definitely use frozen blackberries! There’s no need to thaw them first. Just cook them from frozen, and you may need to add a minute or two to the cooking time.

More Desserts You’ll Adore

If you loved the elegant simplicity of this cake, you have to try my Lemon Lavender Pound Cake—it has a similar vibe that’s perfect for tea time or a special brunch. For another dessert that uses fresh fruit in a stunning way, my Rustic Peach Galette is always a crowd-pleaser and is much easier than it looks!

This Pistachio Olive Oil Cake is more than just a recipe; it’s a little project that ends with a beautiful, delicious reward. It’s a reminder that baking doesn’t have to be complicated to feel special. The subtle savoriness of the olive oil, the crunch of the pistachios, and the sweet-tart burst of blackberry all come together to create a dessert that feels both wholesome and indulgent. I hope it brings as much joy to your kitchen as it does to mine.