Flour

Flour was a powder created by grinding certain types of plants.

A biscuit was a baked flour-based food often served with tea. (TV: The Invasion, Victory of the Daleks, The Last Precinct)

By 2018, Salamander's Sun Store technology had turned Ukraine into "the grain field of the planet". Although a large area had been devastated just two years earlier, robot harvesters gathered fifty million tons of flour, and corn grew on both banks of the Dnieper River. (TV: The Enemy of the World)

A cake was a baked dessert, typically made of flour and eggs and often bearing some sort of frosting. (AUDIO: The Marian Conspiracy)

The Eleventh Doctor stopped a soup creature by thickening it with flour. (COMIC: In the Can)