01 - Preheat the oven to 350°F. Grease a 9x13-inch baking pan thoroughly with cooking spray or butter.
02 - In a large bowl, combine the strawberry cake mix, eggs, vegetable oil, and water. Mix according to package directions until well blended. Pour the batter evenly into the prepared baking pan.
03 - In a separate bowl, beat together the softened cream cheese and butter until smooth. Add the powdered sugar and vanilla extract, continuing to beat until the mixture is creamy and lump-free.
04 - Drop spoonfuls of the cream cheese mixture evenly over the surface of the cake batter, spacing them out to cover the pan.
05 - Scatter the diced strawberries and white chocolate chips over the top of the batter and cream cheese mixture. Sprinkle with shredded coconut if using.
06 - Using a knife, gently swirl the cream cheese mixture into the cake batter. Make a few figure-eight motions to create a marbled effect, being careful not to overmix.
07 - Bake for 40 to 45 minutes, or until the edges are set but the center remains slightly gooey. The cake should appear molten in the middle when done—do not overbake.
08 - Allow the cake to cool in the pan for at least 30 minutes before slicing. Serve slightly warm or at room temperature for the best texture and flavor.