Baking Powder (Best Option)
1 teaspoon baking powder per 1/4 teaspoon baking sodaBaking powder contains both an acid and a base, allowing it to produce carbon dioxide gas when moistened and heated, which helps the omelette rise and become fluffy. Since it is less potent than baking soda, a higher quantity is needed to achieve the same effect.
When substituting, ensure you use the correct ratio to avoid a metallic or bitter aftertaste. Mix the baking powder thoroughly with the eggs to distribute the leavening evenly.
The final omelette will be slightly lighter and fluffier, with a mild difference in taste that is usually imperceptible, making baking powder the most reliable substitute.