This Walnut Espresso Cake with Buttercream Frosting is the final bake of the year from Aleksandra Crapanzano’s Gâteau: The Surprising Simplicity of French Cakes.

I chose this particular cake for a reason—it’s a delicate, two-layer espresso-infused creation, generously topped with fresh walnuts and coated in a luscious espresso buttercream frosting. And, of course, it’s finished with even more walnuts for the perfect balance of texture and flavor.

From the moment I discovered this recipe, I knew it was one I had to make. It had been on my list from the start, so it felt fitting to end the year with it.

Aleksandra and I have plenty of recommendations and tips for this cake, so let me share them with you.

First and foremost, always have your butter and eggs at room temperature. This has become my golden rule for every bake—it prevents the butter and batter from curdling due to temperature differences.

Another key tip Aleksandra highlights is using unsalted European butter. While I typically prefer salted American butter, I made an exception for this cake and picked up unsalted European butter (Plugrá was available at my store).

To be honest, I didn’t notice a significant difference in the final bake, and I still lean toward salted butter. If you ever substitute salted butter in a recipe that calls for unsalted, simply reduce the added salt slightly—if the recipe calls for 1 teaspoon, I usually cut it down to ¾ teaspoon. Ultimately, it’s all about personal preference.

This cake is at its best the day it’s baked. If you’re not serving it until later in the day or evening, let it cool completely, then wrap it tightly in plastic wrap and keep it at room temperature until you’re ready to frost.

Leftovers should be refrigerated, but keep in mind that chilling the cake will slightly alter its texture, making it less soft and tender.

The original recipe calls for rum in the frosting, but I swapped it for a teaspoon of vanilla since I’m not a fan of rum flavor—except, oddly enough, in LifeSavers Butter Rum candy. Though I’m pretty sure they don’t make those anymore…

But I digress. Back to the cake!

We really enjoyed this cake! One important tip—make sure to toast your walnuts. It enhances their natural oils and deepens the flavor, making a noticeable difference. Trust me, it’s worth the extra step.

Speaking of which, I told Bret I had to go toast my nuts, and of course, he giggled. Men.

To toast walnuts, spread them out on a sheet pan and place them in a 250°F oven. After about 5 minutes, give them a toss, then let them toast for another 5–7 minutes.

And here’s a lesson learned—let them cool before adding them to the cake. In my infinite wisdom, I didn’t wait, and surprise, surprise… they started melting the buttercream. Not my finest moment!

I’m really going to miss baking these simple, delicious recipes, but luckily, I still have the cookbook—and it’s earned a front-row spot in my collection.

If you loved this Walnut Espresso Cake with Buttercream Frosting, don’t miss my Persimmon Spice Cake and Walnut, Pear, and Espresso Cake!