Special equipment: a squeeze bottle, chopstick, butane torch and piping bag fitted with a decorative tip, optional
For the cake: Preheat the oven to 325 degrees F. Grease and flour a 9-by-13-inch cake pan.
In a large mixing bowl, combine the dry cake mixes. Add the eggs, vegetable oil and 2 cups water. Using an electric mixer on a low speed, whisk to combine. Once incorporated, increase the speed to high and mix for 3 minutes. Pour the batter into the prepared cake pan and bake until a skewer inserted into the middle of the cake comes out clean, about 45 minutes. Set aside to cool.
For the strawberry gelatin: Add the strawberries, sugar and 1 cup water to a blender and pureed. Pour into a medium saucepan and bring to a boil over medium-high heat. Lower to a simmer and cook until slightly thickened, about 5 minutes. Remove from the heat and allow to cool completely.
In a large mixing bowl, add the strawberry gelatin and whisk in the strawberry puree. Add 2 cups cold water. Pour into a squeeze bottle and set aside at room temperature while you prepare the cake. (Do not refrigerate.)
Score a 3-by-3-inch grid on the cake. Using the thick-end of a chopstick, poke holes on the score-lines and then randomly within each section. Hold the tip of the squeeze bottle above each hole and fill with the strawberry-gelatin.
Put the cake in the fridge to set for 10 minutes. Remove from the fridge and do one more round of strawberry-filling. Chill again for 10 minutes.
For the meringue: Combine the sugar and 2/3 cup water in a medium saucepan set over medium-high heat. Bring to a boil (or 240 degrees F on a candy thermometer). Pour into a heat-safe liquid measure.
Simultaneously, in the bowl of a very clean stand mixer fitted with the whisk attachment, whisk the egg whites to soft peaks on medium speed. Add the vanilla and cream of tartar. Increase the speed to medium-high, and with the machine running, slowly drizzle in the hot sugar until the meringue is glossy and stiff, 7 to 10 minutes. (Tip: Whisk until the bowl no longer feels warm to the touch.)
Transfer the meringue to a piping bag or a pastry bag fitted with a decorative tip. Pipe the meringue onto the cake and, using a butane torch, toast the meringue until browned. Alternatively, you may use an offset spatula to ice the cake. Cut into squares and serve.
Propane gas torches are highly flammable and should be kept away from heat, open flame and prolonged exposure to sunlight. They should be used only in well-ventilated areas. Follow torch manufacturer's instructions for use.