What can you make with a failed meringue mix?

Presumably you've baked it.

The easiest and tastiest thing you can do is make Eton Mess.

Whip cream. Prepare strawberries and cut them into chunks. Break the meringue into pieces. Fold the strawberries and meringue through the cream - do this just before serving so the meringue retains some crunch. Spoon it into individual glasses.