The story might be apocryphal, but bakers indeed do use cookies to test proportions of ingredients. You’re not going to waste a whole pound of flour just to see the effect of more or less butter in a particular recipe. You do a little bit and bake them in cookie proportions. Specially when you have to make several hundred pounds of cake at a time, you can’t afford to err on the measurements, and you do need to know variations in the flour.
The story might be apocryphal, but bakers indeed do use cookies to test proportions of ingredients. You’re not going to waste a whole pound of flour just to see the effect of more or less butter in a particular recipe. You do a little bit and bake them in cookie proportions. Specially when you have to make several hundred pounds of cake at a time, you can’t afford to err on the measurements, and you do need to know variations in the flour.
Dude, you’re so wrong about all of this. Bakers typically use the same ingredients from the same providers. So they know what to expect.
And when it comes to a dough or batter, a baker can tell by look and feel if the proportions are off and will adjust accordingly.