In a medium saucepan over medium heat, combine the quartered fresh strawberries, granulated sugar, and lemon juice. Stir occasionally, allowing the mixture to simmer for 15-17 minutes, until it thickens and bubbles gently.

Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners. In a mixing bowl, whisk together the cake flour, baking powder, baking soda, and salt.

In another bowl, cream the unsalted butter and sugar together until light and fluffy, about 3-5 minutes. Add in the egg whites and vanilla extract, mixing until just combined.

Alternate incorporating the dry mixture and buttermilk until the batter is smooth.

Carefully fill each cupcake liner about two-thirds full with the batter. Bake for 16-18 minutes, or until a toothpick inserted into the center comes out clean.

Let the cupcakes cool in the pan for 10 minutes before transferring them to a wire rack to cool completely.

While the cupcakes are cooling, prepare the frosting. In a mixing bowl, whip the unsalted butter until fluffy, then add the cream cheese and mix until fully combined.

Gradually add in the sifted powdered sugar, followed by the freeze-dried strawberries, mixing until the frosting is creamy.

Once the cupcakes are cooled, hollow out the centers and fill each hollow with strawberry jam, then pipe the cream cheese frosting on top.

Decorate each cupcake with fresh strawberries for extra sweetness.