There seems to be more uses for egg yolks than for egg whites. I've had to be creative to find ways to use up egg whites. Macaroons of course, but I don't like dry shredded coconut so that won't do. A Pavlova is basically a big meringue so it's easy to make.
4 egg whites
1 cup superfine sugar - icing, berry or regular sugar ground in the food processor
1/2 tsp vanilla
1 tsp white vinegar
1/2 Tbsp corn flour
Whip the egg whites up till stiff then fold in the sugar, vanilla, vinegar and corn flour. Put parchment paper in a 8x8 or so pan and pour the batter into it. Bake at 250 degrees for at least 60 minutes. It should be hard on the outside and a bit runny in the center.
You can use juice from half a lemon instead of vanilla and vinegar but you may need more sugar, taste it and add extra as needed.