Preheat your oven to 350 degrees Fahrenheit. This step is crucial as it ensures that the cupcakes bake evenly. While the oven heats, you can prepare your ingredients.
Sift together cake flour, baking powder, baking soda, and salt in a mixing bowl. Sifting helps to aerate the flour and removes any lumps, which results in a lighter cupcake. Set this mixture aside.
In the bowl of an electric stand mixer fitted with the paddle attachment, whip together unsalted butter and granulated sugar until the mixture is pale and fluffy. This can take about 3 to 5 minutes. Scrape down the sides of the bowl occasionally to ensure everything is well combined.
Add in one large egg, mixing until fully incorporated, then add the two large egg whites, one at a time, ensuring each is blended in before adding the next. The eggs add moisture and structure to your batter.
In a liquid measuring cup, whisk together the buttermilk, strawberry puree, and vanilla extract. This wet mixture will add flavor and moisture to your cupcakes.
Gradually add one-third of the flour mixture to the butter and sugar mixture, alternating with half of the buttermilk mixture. Begin and end with the flour mixture, mixing just until combined after each addition. Be careful not to overmix as it can lead to dense cupcakes.
Gently fold in the diced strawberries using a spatula. This step ensures the strawberries are evenly distributed throughout the batter. You want to see little chunks of fruit in every bite!
Divide the batter among 12 paper-lined muffin cups, filling each about three-quarters full. Aim for even portions, using a 1/3 cup measure can be helpful here. This will make sure all your cupcakes bake evenly.
Bake in your preheated oven for 20 to 23 minutes. The cupcakes are done when a toothpick inserted into the center comes out clean. Let them cool in the muffin tin for several minutes before transferring to a wire rack to cool completely.
While the cupcakes are cooling, it’s time to make the strawberry buttercream frosting. In a small saucepan, heat the strawberry puree over medium-low heat, simmering until it reduces to about 3 tablespoons. This usually takes about 10 to 14 minutes. Let it cool after reducing.
In a clean mixing bowl, whip together the unsalted butter and salted butter until pale and fluffy. This might take about 5 minutes. Again, be sure to scrape the bowl down as you go.
Gradually mix in 1 cup of powdered sugar, followed by 3 tablespoons of your cooled strawberry puree and vanilla extract. Mix on low speed until combined. Then add the remaining powdered sugar, continuing to mix until the frosting is light and fluffy. You can add more powdered sugar if necessary for the desired consistency.
To assemble, place a small mound of diced strawberries on top of each cooled cupcake. Pipe the frosting around and over the berries, topping each with a whole small strawberry. This final touch adds both beauty and flavor!
Store your cupcakes in an airtight container to keep them fresh. Enjoy your homemade Strawberry Cupcakes with friends and family!
