Preheat oven to 350 degrees F. Spray a 9 x 13-inch baking pan to prevent sticking.
Spread marshmallows evenly over the bottom. Mix cake as directed on box and pour batter over the marshmallows. Sprinkle the dry gelatin powder over the cake batter. Let strawberries thaw slightly, but do not drain. Spoon here and there over gelatin. With a spoon, drizzle water evenly over the strawberries. Do not stir.
Carefully place the pan on the center rack of preheated oven. Bake 55 to 60 minutes, or until it tests done with a toothpick in the center and the top is golden brown.
Cool in pan at least 30 minutes before serving. Store any leftovers in the refrigerator. You can top with whipped cream or ice cream, if desired. When serving you will ss that the marshnallows are now on top and the strawberries are on the bottom. This freezes well.