Identify the egg’s job in your recipe: binding (gel/thickener), emulsifying (aquafaba), or lift (baking powder + vinegar).
Choose the substitute with the closest texture goal: foamy for lift, gel-like for binding, or smooth for custards.
Apply the swap using the ratio in the table above; for gels, mix and rest until thick before adding to batter.
If the batter looks too thin, add a small amount of extra binder (more gel or a teaspoon of starch); if too thick, loosen with a splash of water/plant milk.
Bake as directed and check doneness (egg substitutes can set slower in the middle); cool fully for best structure.