Prepare White Cake
1-Preheat oven to 350F: Preheat oven to 350F.
2-Grease and sprinkle with flour a 9-x-13: Grease and sprinkle with flour a 9-x-13 inch cake pan.
3-Prepare white cake mix according to box: Prepare white cake mix according to box instructions. Pour batter into the prepared pan and bake for about 25-30 minutes, or until a toothpick inserted in the center comes out clean. Let cool for 10 minutes and using the bottom of a wooden spoon, poke holes all over the cake, 1 inch apart.

Strawberry White Chocolate Mixture
4-In a medium, microwave-safe bowl, combine white: In a medium, microwave-safe bowl, combine white chocolate chips and sweetened condensed milk. Heat in the microwave until hot for about 1 minute, stir and heat for 30 seconds or more if needed. Stir until fully combined, smooth, and shiny.
5-Stir in the strawberry gelatin and mix: Stir in the strawberry gelatin and mix into the warm water. Make sure it dissolves, otherwise it will be gritty. Stir the strawberry mixture into the condensed milk mixture until fully combined and smooth.
6-Pour the strawberry chocolate mixture all over: Pour the strawberry chocolate mixture all over the cake and using a spatula spread it evenly into the holes.
7-Let the cake cool completely and refrigerate: Let the cake cool completely and refrigerate for about one hour.

Other layers
8-Top the cake with the strawberry pie: Top the cake with the strawberry pie filling if using.

Whipped Cream
9-In a large bowl, beat heavy cream,: In a large bowl, beat heavy cream, sugar, and vanilla extract until stiff peaks form.
10-Using a spoon, scoop the whipped cream: Using a spoon, scoop the whipped cream all over the cake and spread it with a spatula.

Garnish
11-Garnish the cake with sliced strawberries: Garnish the cake with sliced strawberries.
12-Refrigerate the cake for at least 8: Refrigerate the cake for at least 8 hours or better overnight before serving.