Which main ingredient can replace solid chocolate in a chocolate brownie batter?

Cocoa powder can replace solid chocolate in chocolate brownie batter. It supplies concentrated cocoa flavor without the cocoa butter and added sugar found in many solid chocolate products, so the recipe usually needs its fat and sugar amounts adjusted to preserve the intended texture.

Early brownie recipes often used melted chocolate and butter together. Later recipes, including versions documented in The Settlement Cook Book, used cocoa powder as an alternative to solid chocolate. The result can still be deeply chocolatey, but the balance of ingredients matters: cocoa powder absorbs liquid, while solid chocolate contributes both cocoa solids and fat.

This substitution is not the same as replacing chocolate with a sweet syrup. Molasses and maple syrup add sweetness and moisture but do not provide the same concentrated cocoa solids. Peanut butter changes the flavor and fat profile as well. Another common source of confusion is hot cocoa mix, which usually contains sugar and milk ingredients and is not equivalent to unsweetened cocoa powder in a baking formula.