Preheat the oven to 350°F (175°C). Grease a loaf or cake pan with butter or non-stick spray and set aside.
In a large mixing bowl, use an electric mixer or whisk to beat softened butter and granulated sugar until the mixture is light, fluffy, and pale in color, about 3-4 minutes. You should see increased volume and a creamy texture.
One at a time, add eggs to the mixture, mixing well after each addition until fully incorporated. Stir in vanilla extract. The batter should become smooth and slightly thickened.
Gradually add sifted flour in three parts, alternating with milk in two parts, beginning and ending with flour. Mix on low speed or fold gently until just combined. Do not overmix to keep the cake tender.
Mix the chopped strawberries into the batter, folding gently until evenly distributed. In a separate bowl, blend softened cream cheese with powdered sugar until smooth to create the swirl mixture.
Pour half of the batter into the prepared pan. Dollop spoonfuls of the cream cheese mixture over the batter, then layer with the remaining batter. Use a knife or skewer to swirl the cream cheese into the batter, creating a marbled effect.
Bake for 55-60 minutes, or until the top is golden and a toothpick inserted into the center comes out clean. The edges should be slightly crisp and the center moist but not runny.
Allow the cake to cool in the pan for 15 minutes, then transfer to a wire rack to cool completely before slicing. Serve slices with additional fresh strawberries if desired.
