Pre-heat oven to 140°C (fan-forced). Grease a 6cm deep and 20cm round cake tin and line the base with baking paper.
Place the cake mix, butter, eggs and water into a medium mixing bowl. Using an electric mixer beat on low speed for 30 seconds to combine. Increase speed to medium and beat for 2 minutes, scrapping down the sides of the bowl occasionally. Pour the batter into the prepared cake tin.
Place in the oven on the middle shelf. Set timer to 30 minutes.
While the cake is baking, prepare the meringue by adding the water to a high sided bowl. Carefully add the Pavlova Magic mix and mix on low speed for 15 seconds to incorporate. Then mix on high speed for 4-7 minutes, scraping down the sides of the bowl occasionally until the mixture is stiff and forms peaks. With the mixer off sprinkle the sugar evenly into the mix. Mix on high speed for 1 minute.
Once oven alarm sounds, remove half-baked cake. Using a large offset spatula quickly spread ½ the meringue mixture on top of cake.
Lower heat to 120°C to ensure cake is not over baked. Bake until meringue is lightly browned and crisp, about 30 minutes. Turn oven off and allow cake to cool. Do not open oven door.