Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, or line them with parchment paper for easy removal.
Prepare the Cake Batter: In a mixing bowl, combine the diced strawberries and 1/4 cup of granulated sugar. Set aside and let them macerate for about 10 minutes to release their juices. In a separate large mixing bowl, cream together the softened butter and remaining granulated sugar until light and fluffy. Beat in the eggs, one at a time, followed by the vanilla extract. In another bowl, sift together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, alternating with the milk, and mixing until well combined. Gently fold in the macerated strawberries until evenly distributed throughout the batter.
Bake the Cake: Divide the cake batter evenly between the prepared cake pans, smoothing the tops with a spatula. Place the cake pans in the preheated oven and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Remove the cakes from the oven and let them cool in the pans for 10 minutes before transferring them to wire racks to cool completely.
Prepare the Frosting: In a mixing bowl, beat the softened butter until smooth and creamy. Gradually add the powdered sugar, one cup at a time, beating well after each addition, until the frosting is thick and fluffy. Beat in the pureed strawberries, vanilla extract, and a pinch of salt until the frosting is smooth and well combined.
Frost and Assemble the Cake: Once the cake layers are completely cooled, place one layer on a serving plate or cake stand. Spread a layer of frosting evenly over the top of the cake layer. Place the second cake layer on top and frost the top and sides of the cake with the remaining frosting. Garnish the cake with fresh strawberries or strawberry slices if desired
Serve and Enjoy: Slice the homemade strawberry cake and serve it to your delighted guests. Store any leftovers in an airtight container in the refrigerator for up to 3 days.