[Reason]

Ble fryktelig usikker selv nå, men etter å ha googlet litt, ser det ut som det vanligste er å bruke strøkne skjeer:

"When used for solids, such as granulated sugar, it should be measured to the flattened level of the spoon—level spoonful versus a heaping spoonful or heaped tablespoon, which is as much as can be held in the spoon, or a rounded spoonful, which is twice a level spoonful, the solids above the level roughly mirroring those in the bowl."

"One heaping tablespoon of sugar may not be equal to another heaping tablespoon of sugar. Recipes usually call for level teaspoons and tablespoons since one level spoonful is more likely equal to another level spoonful than two heaping spoonfuls are equal to each other."

Og herfra:

"If a recipe calls for a level teaspoonful of a dry ingredient (salt, flour, etc.), this refers to an approximately levelled filling of the spoon, producing the same volume as for liquids.
A rounded teaspoonful is a larger but less precise measure, produced without levelling the ingredient off nor heaping it as high as possible.
A heaping (American English) or heaped (British English) teaspoonful is a larger inexact measure, equal to the most that can be obtained by scooping the dry ingredient up without levelling it off. For some ingredients, e.g. flour, this quantity can vary considerably.
When no particular type of teaspoonful is specified for a dry ingredient it may mean a level or a rounded spoonful, never a heaping/heaped one."