Preheat your oven to 350°F (175°C). Lightly grease and flour a 9x13 inch baking pan, or line it with parchment paper for easy removal.

In a large mixing bowl, combine the white cake mix, 1 cup milk, vegetable oil, and 3 large eggs. Beat with an electric mixer on medium speed for 2 minutes, scraping down the sides of the bowl as needed, until the batter is smooth.

Gently fold in the 1 cup of finely diced fresh strawberries into the cake batter. Pour the batter evenly into your prepared 9x13 inch baking pan.

In a separate medium mixing bowl, beat together the softened cream cheese and softened unsalted butter with an electric mixer until smooth and creamy, about 1-2 minutes.

Gradually add the 2 cups of sifted powdered sugar, beating until fully incorporated. Add the 1 tsp vanilla extract and 2 tbsp milk (or heavy cream), and beat until the filling is light and fluffy.

Dollop spoonfuls of the cream cheese filling evenly over the top of the cake batter in the pan. You don't need to spread it, just drop it in mounds.

Scatter the 1 cup of sliced or chopped fresh strawberries and the 1/2 cup white chocolate chips over the cream cheese dollops and cake batter.

Warm the 1/4 cup strawberry jam slightly (a few seconds in the microwave works) to make it more liquid. Drizzle the warmed jam over the entire cake in a swirling pattern.

Bake for 30-35 minutes, or until a wooden skewer inserted into the cake (avoiding the cream cheese dollops) comes out clean. The top will be golden brown and the cream cheese will be set and lightly browned.

Let the cake cool in the pan on a wire rack for at least 30 minutes. As it cools, the 'earthquake' cracks will become more prominent.

While the cake cools, prepare the optional glaze: In a small bowl, whisk together 1 cup powdered sugar, 2-3 tbsp milk, and 1/2 tsp vanilla extract until smooth. Adjust milk for desired consistency.

Once the cake has cooled sufficiently, drizzle the glaze over the top. Allow the glaze to set slightly before slicing and serving.