Preheat the oven to 350℉ and spray a 9x13-inch baking pan with non-stick spray or solid vegetable shortening.
Make the cake according to the box's directions and add a 3-ounce package of strawberry gelatin (Jello). (Don't make the Jello, just put the dry mix in.) bake in a 9x13 baking dish using the time indicated on the cake mix box as a guide.
When the cake is done and still warm poke holes in the cake with a long skewer or butter knife.
Slowly pour the condensed milk over the cake allowing it to soak into the holes and the edges of the cake.
Cover and refrigerate until the cake is chilled. (You can do the next step when the cake it chilled or wait until you're ready to serve it.)
Mix the whipped topping and 2 tablespoons of white chocolate instant pudding together carefully to not deflate the whipped topping. Spread the mixture over the chilled cake.
Serve or refrigerate until ready to serve. Garnish with strawberries before serving.