Rescues · TO MEASURE
Baked goods come out inconsistent between attempts with the same recipe.
Why it happens
Volume measurement of flour and sugar. The recipe is fine; the measurement is not reproducible.
Recovering it
A dough that came out stiff can be corrected with water, a spoonful at a time, until it feels right — which is the real argument for learning what the dough should feel like rather than trusting the number. A batter already in the tin cannot be corrected. For anything where the ratio matters, the durable fix is a scale: it costs almost nothing, removes the whole class of error, and means a recipe behaves the same every time.
The mechanism
A measuring cup measures space, not substance, so it is only reliable for things whose density does not change. Water and oil are consistent to within a percent or two. Flour is not: the same cup can hold 110 g scooped straight from the bag and packed, or 125 g spooned in and levelled, a difference of over ten percent that shows up directly in a dough's hydration. Brown sugar varies more still, depending entirely on how hard it was pressed. This is why baking recipes that matter give weights and cooking recipes usually do not — a stew is forgiving of ten percent more onion, and a bread is not. Small volumes are the exception in the other direction: a quarter teaspoon of yeast is beyond the resolution of any domestic scale, so spoons win there.
The full TO MEASURE lesson — how to tell, where to practise it, what it carries to.