It's happened to all of us; you put all the ingredients into the cooking slots, then you leave the page, forgetting the click the button.

The forms have been changed, so there should be a confirmation button for those who choose to leave the page prematurely, at least if the ingredients in the slots match a valid recipe. If they don't, the game could take that as "not enough ingredients" and not warn the player before leaving the page. We already have a similar check for when you DO click the button, but don't match a recipe, so it shouldn't be hard for the game to perform a similar check when the player tries to leave the page.