"Think of it as foreplay for fruits and vegetables."
While blanching may not be the technique with the most mystique—you bring the water to a boil, drop in the goods, then shock them in ice water to stop the cooking—the benefits of blanching are where the allure's at.
Blanched foods heat quickly so they retain color and texture, are depleted of their excess water (seems backwards, right?), and cook evenly so they're less likely to scorch or wilt during sautéing, frying, or other preparations that might happen later. In addition, ones you might normally find bitter, like greens, or fibrous, like carrots, become noticeably less so after a quick jacuzzi.
That's why many vegetables in the professional kitchen are first blanched before any other prepping or flavoring is done.
No doubt you've heard the self-defamating beginner cook crack the "I can't boil water" joke. Truth be told, culinary school taught me some things I didn't know about the technique. Here are a few pointers.
Start with more water than you think you need. It'll take longer to boil, but a greater water-to-veggie ratio means the temperature will drop less, so food will cook more quickly and retain better color and bite. Blanching in small batches also helps this effort.
Second, salt the water way (way) more heavily than you think you should. We're talking palmfuls. At least one, maybe two.
Next, keep close watch once you add the ingredients. Depending on the food and what kind of post-blanching cooking you're planning, the item could be ready to come out as quickly as 30 seconds to a minute. Watch for brightening of color and test for desired texture.
And last, have a shock bath—ice and enough cold water to cover it—ready in advance to stop the cooking process. If you drop in your veggies and only then realize you're out of ice, you're in trouble.
It's the trick that keeps on giving. You can zap basil leaves before making pesto to get a bright green batch, blanch stone fruits or tomatoes to easily slip off their skins (just cut an "X" in the bottom before boiling so the skins can loosen), or prep for dinner parties a day in advance.
The best part: You'll never let a veggie go to waste in your crisper drawer again. Now, that's sexy.