Cooks who whip up wonderful meals at a moment’s notice invariably rely on a simple strategy: They start with the freshest, highest-quality ingredients available. They know that the more great flavor the components have to begin with, the less you have to work to make the dish taste divine. By keeping special staples on hand — high-end olive oil, salt, and butter, to name a few — you can quickly transform ordinary food into stylish, satisfying meals. Here’s the short list of important culinary splurges, along with recipes that come to life because of them.