Creaming butter and sugar
Beating soft butter with sugar drags sharp crystals through the fat and traps tiny air pockets. In the oven, steam and baking powder gas fill those pockets and stretch them. That gives the bake a fine, tender crumb and lift.
Butter should not be too warm
Butter at about 18°C (65°F) holds air best. It dents under your finger without feeling greasy. If it's shiny or melty, the air pockets collapse and the bake turns flat and oily. Beat 3 to 5 minutes, until pale and fluffy.
Test yourself
Questions from the interactive lesson, with the answer and the why.
What do the air pockets from creaming do in the oven?
Give lift and a fine crumb. The pockets expand in the oven.
True or false: Butter straight from the fridge creams just as well as softened butter.
False. Cold butter is too hard for sugar to cut air into. Soft butter dents under a finger.
What went wrong? You microwave butter until it's half melted, cream it with sugar and bake. The cookies come out flat and greasy.
Partly melted butter can't hold air. Use butter that is softened but still solid.
Fill the blank: Well-creamed butter and sugar looks pale and ___.
Well-creamed butter and sugar looks pale and fluffy. Air has been beaten in.
Why add eggs one at a time when creaming?
So each one blends in and the batter stays smooth. Each egg is mixed in fully before the next, so the batter stays blended.