Thecookinginn.com says:
To make one egg use 2 tbsp water and 2 tsp baking powder
Kidswithfoodallergies.com says:
3-1/2 tablespoons gelatin blend (mix 1 cup boiling water and 2 teaspoons unflavored gelatin, and then use 3-1/2 tablespoons of that mixture per egg)