Vanilla Cake + Balsamic Roasted Strawberry Buttercream

Three layers of vanilla bean cake, frosted with balsamic roasted strawberry buttercream and topped with a mountain of balsamic roasted strawberries.

Last weekend, I got to go on a little farmer’s market date with my mom. We share a mutual love for strolling through all the stalls of farm-fresh vegetables and artisan baked goods on a sunny Saturday morning. It’s a very good bet you can find us there almost every weekend throughout the summer.

But now that I’m out of the house, it’s rare that we get to go together. So, it was kind of a special occasion and we took that as an obvious excuse to share a warm chocolate almond croissant as we browsed. Together, we sampled all the freebies, picked out some vegetables for my dad (he’s the chef in the family), and bought boxes and boxes of strawberries so that I could bake this cake. I’ve had the idea for this balsamic roasted strawberry buttercream cake in my head for ages, and I knew I had to finish testing it for you before strawberry season passed me by again.

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Vanilla Bean Cake

For the actual cake, I kept things pretty simple–  three layers of a classic vanilla bean cake with a tender crumb. It’s lovely and it serves as the perfect canvas for the strawberry buttercream. I highly recommend using vanilla bean paste (rather than vanilla extract) to flavor the cake.

Vanilla bean paste is what many would consider the happy medium between vanilla extract and scraping out an actual vanilla bean. It provides all the convenience of extract without sacrificing the appeal of actual flecks of vanilla bean and a more concentrated flavor. I’ve switched over to using vanilla bean paste in most of my recipes and I love being able to see those flecks in my finished baked goods! It’s a one-to-one substitute for vanilla extract, so you can easily put it to the test in some of your favorite recipes.

Balsamic Roasted Strawberries

Now, for the most exciting part of this cake… for the frosting and garnish, you’ll need TWO pans of balsamic roasted strawberries. If you’ve never had roasted strawberries before… let me tell you, you’re in for such a treat! Roasting the berries brings out and intensifies their flavor in the best way. And the addition of balsamic vinegar becomes a subtly tangy complement for the sweet strawberries and sugary frosting.

I actually have an extra batch of these balsamic roasted strawberries in my fridge as we speak, and they are perfect for eating by the spoonful serving on top of all sorts of things – ice cream, pancakes, yogurt, goat cheese, etc. But if we’re being real, mostly I’ve just been eating them by the spoonful because they’re sooooo good. You’ll probably want to do the same thing, but I promise it’s worth it to make sure you have enough for this roasted strawberry buttercream! And I insisted on making an entire double batch because I wanted a mountain of berries to put on top of the cake.

Buttercream Rosettes

To avoid adding too much liquid to my frosting, I let half of my strawberries roast a little bit longer in the oven, so they were more caramelized and slightly “drier”. This is the batch that I pureed (using a blender or food processor), then added to the buttercream one tablespoon at a time. I ended up using 5 to 6 tablespoons of puree, which left me with a still-stable buttercream for piping.

You can frost this cake however you like, but here’s a quick tutorial for the rosettes (they’re easier than you’d think!):

1. Fit a pastry bag with a large open or closed star decorating tip and fill it with the strawberry buttercream.
2. Start at the base of the cake and pipe a row of rosettes all the way around the cake, covering the bottom third of the cake. For each rosette, start at the center and pipe a swirl, moving in an outward direction from the center. Slowly ease the pressure off the piping bag as you get to the end of the rosette and let the tail trail off (in the direction you are piping).
3. You can cover the tail of the previous rosette with the next one, letting the rosettes slightly overlap each other.
4. Pipe the second row of rosettes, starting the center point of each rosette directly above the place where two of the rosettes in the bottom row overlap (so the roses alternate position from a vertical perspective). Repeat with the third row of rosettes.
5. Store the cake in the fridge to help the rosettes set and hold their shape.

To Prepare In Advance

The roasted strawberries should be stored in an air-tight container in the fridge and will keep for at least a week. The cake layers can be wrapped tightly in saran wrap and stored either at room temperature for a day, or in the freezer for longer. Once frosted, the cake can be stored (covered) at room temperature for a day, or in the fridge for 2-3 days. I recommend garnishing with the balsamic roasted strawberries shortly before serving.

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