Strawberry Buttercream Cake

cake iced

I love a good slice of cake! This buttermilk sheet cake with strawberry buttercream, which Erin whipped up for Taylor’s birthday celebration a couple weeks ago, makes a perfect cake for any occasion. Adding the buttermilk and sour cream result in a tender, anything-but-dry cake. And if you’re not a fan of strawberries, you can easily customize the buttercream icing to your taste! Happy baking!

icing in mixer

cake in pan on cooling rack cake topped with icing and strawberries

Full cake on the edge of the counter

top view of cakes with icing and strawberries Buttermilk Sheet Cake with Strawberry Buttercream
Prep time: 45 minutes
Baking time: 35 minutes
Serves 12

For the sheet cake:
2 ½ cups cake and pastry flour
1 tsp. baking soda
1 tsp. baking powder
½ tsp kosher salt

¾ cup unsalted butter at room temperature
1 ¼ cup sugar
1/3 cup brown sugar
2 large free-range eggs at room temperature
1 large free-range egg yolk
1 cup buttermilk (not cold)
½ cup sour cream
2 tsp. vanilla extract

For the buttercream:
3 large free-range egg whites at room temperature
1 cup + 2 Tbsp. sugar
Pinch of cream of tartar
1 cup + 2 Tbsp. unsalted butter at room temperature
Pinch of sea salt
1/3 cup strawberry jam (or whatever flavour you prefer)

Make cake:
Preheat your oven to 325ºF for a convection oven. (350ºF for non-convection oven)

Line a 9×13 inch rectangle cake pan with parchment paper. (Tip: I like to grease the pan before inserting the parchment paper so the paper actually sticks to the sides when you spread the batter.)

In the bowl of your mixer fitted with the paddle attachment, cream together the butter and both sugars on high. Let this mix for around 3 minutes. Add in your eggs one at a time with a good mix in between each addition.

In a large bowl, sift all of your dry ingredients together.

Mix together the buttermilk and sour cream.

Start to incorporate the dry and wet ingredients together. Alternate between the dry and wet in three additions, always finishing with the dry ingredients.

Spread the batter evenly in the prepared cake pan. Bake in the oven for 30–35 minutes until a toothpick or cake tester comes out clean. The top should be golden brown and spring back when touched.

Let cool.

Prepare strawberry buttercream:
In the extremely clean bowl of your mixer, add in the egg whites along with the 2 Tbsp. sugar and pinch of cream of tartar.

In a small-medium sized saucepan, add the cup of sugar with about ¼ cup of water. (Just enough to make a wet sand texture.) Make sure to wipe down the side of the pot with a pastry brush to ensure there are no sugar granules lurking on the edge.

Place the saucepan over medium-high heat until the sugar reaches 121ºC. Use a candy thermometer to gauge temperature.

While the sugar is boiling slowly, start to whisk the egg whites so they get nice and fluffy.

With the mixer on medium-high, gradually pour in a steady stream of the hot sugar syrup. Go right along the edge of the bowl so the syrup doesn’t catch the whisk.

Keep whisking on a high speed until you have a beautiful glossy meringue and the bowl is cool to the touch.

Change out the whisk for the paddle attachment. Add the butter in small amounts at a time. Keep mixing even if the mixture looks like it split, it will eventually come together. Ultimately, the icing’s texture should be nice and fluffy.

Add in the strawberry jam to flavour. You can also add a touch of gel food colouring if you desire a more vibrant colour.

Once the cake is cool, ice the cake and top with some fresh strawberries and enjoy! This cake can last in the fridge for up to 3 days in a sealed container.

This cake would be amazing with any type of berry: blackberries, raspberries or whatever your heart desires!

Recipe created by MH food editor, Erin Girard.