If a cake has a crunchy crust and compact moist texture, which ingredient should be adjusted?

The ingredient that should be adjusted in this situation is sugar. A cake's texture and moisture level can be significantly influenced by the amount of sugar used in the recipe. When sugar is increased, it not only sweetens the cake but also affects its moisture content and creates a tender crumb by incorporating air during the creaming process.

If the cake has a crunchy crust yet is compact and moist inside, it could indicate that there is not enough sugar to adequately balance the moisture in the batter, leading to a dense texture rather than a light and airy one. Reducing sugar may lead to a less crunchy crust, but if it's adjusted properly, it can enhance the overall texture by retaining more moisture while ensuring the crust remains pleasant.

Flour contributes to the structure of the cake, while milk impacts moisture and richness, and baking powder is responsible for leavening. While these ingredients play crucial roles in determining the final outcome of the cake, in this particular context, adjusting sugar is vital for correcting the compact texture and crunchy crust.