I eschew par cooking.  Nothing seems so tedious or redundant to me than cooking something prior to cooking something.  Recipes that ask you to fill a big pot of water, wait for it to come to a boil so you can then par boil ingredients in batches, shock them in another big bowl of ice water, then assemble a casserole which will bake for another hour, beg the question of why anyone would dirty all those extra dishes for something that will spend so much time in the oven.  Is broccoli really that resilient?

Par cooking is an example of a restaurant technique necessary for complex dishes that require quick assembly.  If you cook everything to perfection in advance; you can quickly reheat it for service.  It also helps in predictability.  When you cook various ingredients in a casserole, for example, the potatoes and squash will cook at different rates.  Par cooking levels that playing field.

However, other techniques exist. Cut tough ingredients into smaller pieces and quicker cooking ingredients into larger ingredients. Use ingredients that weep fluid while cooking which will keep the casserole moist and create almost an internal water bath but match these with starches to soak up that liquid. Cook the casserole on a moderate heat for a long period to ensure the ingredients cook through.  There are many methods one can use that don’t require taking extra steps to dirty more dishes than necessary, robbing the ingredients of flavor.

For a more ridiculous example, think of how many recipes call for par cooking before sautéing something. Again, a restaurant rationale for a la minute presentation. The only case where this technique has any credibility involves bitter vegetables. Broccoli rabe, for example, benefits from a par boil to leach out some of the bitterness before sautéing.

In fact, the concept of boiling vegetables prior to service sprung from the opinion, of some, that vegetables were distasteful and improved by leaching out the natural flavor and substituting butter and salt.

Now that we have come to appreciate vegetables more, and cook them at home no less, we can ditch the old-fashioned restaurant preparation and cook vegetables in ways that concentrate their flavor. Sautéing, grilling, roasting, broiling and eating in their natural state all preserve the nutrients and flavor of vegetables. They also save time and require less dishes to clean.