Wash the lemons. Make sure to remove any waxy residue.
Trim the ends and discard.
Slice into ¼ inch slices and remove the seeds.
Combine the sliced lemons, lemon juice, water, and salt in a small saucepan and simmer over medium-low heat and cover. TIP: Check often to make sure the liquid hasn't evaporated. Add more water or lemon juice if needed.
Simmer until the rinds are tender and translucent, 10-15 minutes.
Let cool completely.
Transfer to a blender and puree until thick and smooth (think baby food consistency). If too thick, add water or more lemon juice, 1 teaspoon at a time.
This SHOULD make ¼ cup lemon puree. For egg replacement, you want ¼ cup puree per egg.
