Baking Powder (Best Option)
1 teaspoon per 1 cup of flour or batter equivalentBaking powder is a chemical leavening agent that releases carbon dioxide when moistened and heated, creating lightness and slight aeration. In tiramisu, which is traditionally not leavened by yeast, baking powder can help maintain a soft, airy texture if any leavening is desired.
For best results, incorporate baking powder evenly into the mascarpone mixture or ladyfinger batter if making from scratch. Avoid overmixing to preserve the delicate structure.
Compared to yeast, baking powder does not contribute to flavor complexity but preserves the creamy, smooth texture essential to tiramisu, making it the most suitable substitute.