Homemade Strawberry Cake

Ingredients
Strawberry Puree
1 pound (454g) fresh strawberries, rinsed and hulled
Cake
2 and 1/2 cups (285g) cake flour (spooned & leveled)
2 teaspoons baking powder
1/2 teaspoon baking soda
1 teaspoon salt
3/4 cup (12 Tbsp; 170g) unsalted butter, softened to room temperature
1 and 3/4 cups (350g) granulated sugar
5 large egg whites, at room temperature
1/3 cup (75g) sour cream or plain yogurt, at room temperature
2 teaspoons pure vanilla extract