Even faster way of leveling cooking is to extract 0.1KG units of meat over and over and cook them, e.g. harvesting meat from a rabbit and cancelling ("Esc") as a split second after as it starts. These tiny nuggets give full cooking experience, so 1.0KG of meat instead gives 10 experience (0.1 x 10) instead of just 1.

Harvesting is in-game-hour based. So trapping and harvesting guts and hides from rabbits is a very quick and safe way to level it to max.