Lemongrass Cake with Key Lime Frosting

It feels like a strange time and yet the perfect time to be baking a cake. All of this time at home really gives us time to sit and reflect, and feel thankful for everything most important – health, family and friends. With that feeling in mind, I decided to bake something cheerful: a lemongrass cake.

This cake is delicious, extra tender, and infused with aromatic and citrusy lemongrass. It took some thought on how to get the cake to actually taste like lemongrass without getting overpowered by other flavours, since lemongrass has a very subtle flavour. The result – amazing. And I whipped up the most delicious key lime frosting to pair it with!

The frosting is creamy, just sweet enough, and has perfect tangy citrus flavour. I’m in cake heaven. And with all this time at home, I decided to decorate it with pretty buttercream flowers. This isn’t a tutorial for those, but I will share which tips I used and colours I blended.

What is lemongrass?

Lemongrass is a tropical, aromatic grass that has the subtle flavour of lemon but without the tart bitterness. It grows in Asia, Africa, and Australia. It is a popular ingredient in Asian cuisine, and you’ll find its fragrance in perfumes. It’s also used medicinally.

Lemongrass contains Vitamin B9, Vitamin C, Magnesium, Phosphorus, Iron, Zinc, and trace amounts of Vitamin A, Selenium, and other B Vitamins. Umm… excuse me? A delicious, vitamin-infused cake? Yes please! Check out this article if you’d like more information on how lemongrass can benefit your health.

How to make lemongrass cake:

Because lemongrass has such a subtle flavour, we are going to infuse the cake with it in two ways: lemongrass milk and lemongrass paste. To make lemongrass milk, start by cutting your lemongrass stalks into quarter inch slices.

Put the lemongrass into a small saucepan with a cup of milk. Bring the milk and lemongrass just almost to a boil then reduce the heat and let it simmer for four minutes. As soon as the milk heats up be sure to stir frequently to prevent the milk from burning. Remove the saucepan from the heat and allow it to steep for ten minutes. Strain the milk into a measuring cup. You want to have two thirds of a cup, so top it up with more milk if needed. You can discard the lemongrass pieces.

This recipe makes a double layer six inch cake. Grease the pans with butter, cover the bottoms with parchment paper, then flour the sides. Preheat the oven to 350 degrees.

In a medium bowl, whisk together the flour, baking powder, and salt. Set it aside for now. Then you are going to cream the butter and sugar together until pale and fluffy. You can mix this cake by hand, but I used my Kitchenaid stand mixer. I mixed them on medium-high with a paddle attachment for about three minutes.

Reduce the speed and mix in one egg at a time, followed by your vanilla extract. Next you are going to alternate additions of the dry ingredients and lemongrass milk in this order – dry, milk, dry, milk, dry. Make sure that everything is well mixed between each addition. Finally, mix in the lemongrass paste. Pour the batter evenly into your two prepared cake pans. I like to use a scale to make sure they are even.

Bake the cakes for approximately thirty-five minutes. Check doneness by inserting a toothpick into the center. You want it to come out almost clean. Make sure not to over-bake as you would lose the tenderness of this delicious lemongrass cake, as well as some of that subtle lemongrass flavour.

Once the cakes are finished, allow them to cool in their pans for ten minutes before turning them out on a cooling rack to cool the rest of the way. Now to move on to the frosting..

How to make key lime frosting:

Key limes – the adorable, miniature version of the citrus we know and love. These limes are less tart and more aromatic than the Persian lime (standard grocery store variety). This makes them perfect for this frosting.

I have to say, I’m really not a frosting lover. But after making up this frosting I think I have changed my mind. I was licking it off the spoon. It’s so good! I can’t stand sickeningly sweet icings. This one is just a little bit sweet with the perfect tanginess.

Using your stand mixer (or elbow engines), mix the butter, zest, and vanilla extract together on medium speed until nice and creamy. Add in one third of icing sugar. Mix. Add in one tablespoon of lime juice. Mix. Another third of icing sugar. Mix. Other tablespoon of lime juice. Mix. Final third of icing sugar. Mix, then mix in a tablespoon of milk. You can add more milk to adjust consistency if desired.

This recipe makes just enough frosting to give a thin layer on this cake. If you love thick frosting (and believe me, you will love this one), make extra.

Once the cakes have cooled, you can begin to decorate them. If your cakes baked with a rounded top, you can cut it off with a cake leveler or sharp knife to have a flat top. Using wet cake strips wrapped around your pans while baking can make them bake more level. I found that these cakes baked up almost completely flat for me. I used a very sharp, serrated knife to carefully even out the top just slightly.

Coat the top of the first cake with a layer of key lime frosting. Place the second cake on top and cover it with the remaining frosting.

Buttercream Flowers:

If you’re interested in the flowers that I did, I made them with a simple buttercream frosting. The icing colours were as follows: green (moss green with a touch of brown), white (just a tiny bit of violet to cancel out the yellows of the butter frosting), and yellow (golden yellow).

I used a Wilton 70 tip for the leaves and a PME 58R petal tip the flowers. The rest was done with just a small hole cut into the tips of icing bags. A curved drying rack (pictured below) gives the flowers some shape as they dry if you don’t want them to be flat.

Such a pretty and yummy cake! I hope if you make it that it will boost your spirits as it did for mine.

Another tasty cake that I made recently is my Irish Farmhouse Apple Cake. If you’re in the mood for baked apples and cinnamon, give it a look.

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