Preheat oven to 350 degrees. Combine cake mix, water, pineapple juice, eggs and oil and mix until combined. Pour into a well-greased and floured 12-cup bundt pan; spread out evenly. Next, combine cream cheese, butter and cornstarch and mix until smooth and creamy. Add the egg, vanilla and sweetened condensed milk and mix until well combined. Spoon cheesecake layer over the top of the cake batter, in an even ring, being careful not to touch the outer or inner part of the bundt pan. Bake in preheated oven for 50-55 minutes or until a toothpick inserted in the center comes out clean.
Cool in pan for 10 minutes, then invert to a wire rack and cool completely. Once cool, top with glaze. For the glaze: Add white chocolate chips to a medium bowl and microwave until melted, stirring every 30 seconds. Stir in the powdered sugar. Add the vanilla and one Tablespoon of pineapple juice and stir until smooth and well combined. If mixture is too thick, add a little more pineapple juice. Drizzle over cooled cake. Allow glaze to set, then slice and serve. Store in the refrigerator until serving.
Note: You can use any flavor of cake mix you prefer, just prepare it according to the ingredients on the back of the box.