Blanching and shocking is nothing more than plunging vegetables into boiling, salted water to cook them until they are still firm, yet soft enough to bite into, then plunging them into an ice water bath to halt the cooking process. Simply drain and store in a container in the fridge to pull out at a moment’s notice. The beauty of blanching is that you can use the same boiling water for all vegetables; just be sure to begin with cauliflower and move on to the haricots verts and broccoli to prevent the white florets from taking on a green tinge. One bonus is that the leftover cooking water makes a light vegetable stock that you can use in soups, to thin sauces, and deglaze pans.
Blanching is simple and the best results come if you use a pot big enough to allow the vegetables to move around freely. Also, be sure to liberally salt the water. I don’t give amounts here; I leave it to you to blanch as much as you think you may need for the week (but don’t forget to add enough to snack on). Leftovers are a gift: You can chop and toss any and all of these into an omelet, throw into a pot with some stock and whir into a soup (add Greek yogurt and fresh soft herbs), or toss with pasta.
Bring a large pot of salted water to a boil. Prepare an ice bath in a large bowl. Line a baking sheet with paper towels.
Meanwhile, prepare the vegetables:
Cauliflower: Remove the green leaves from the cauliflower and discard. Cut the head in half lengthwise and cut out the solid stem and core entirely. Break into big florets by hand. Using a knife, trim the larger pieces into ½- to 1-inch pieces (or a size that is comfortable to put in your mouth). Cut the stalks into ⅛-inch-thick slices.
Broccoli: Remove the green leaves from the broccoli and discard. Cut away the tough portion of the stem and discard. Using a knife, separate the florets into ½- to 1-inch pieces (or a size that is comfortable to put in your mouth). Cut the stalks into ⅛-inch-thick slices.
Haricots verts: Trim the stem ends.
Broccoli rabe: Cut stalks with leaves into ½-inch pieces on the diagonal and cut florets off the stalk whole.
Blanch the vegetables—Working in batches so that the water continues to boil, dump the vegetables, one type at a time, working from lightest to darkest, into the boiling water. Cook, checking every 30 seconds, until a knife pierces the vegetable with a little effort. You don’t want them cooked all the way through because you will be reheating them. To test, use a slotted spoon to remove one vegetable and dip into the ice water. Taste for doneness. The vegetable should be firm to the bite and look vibrant.
Shock the vegetables—Using a slotted spoon, transfer the vegetables to the ice water to stop the cooking process (and to preserve the boiling water, which is now a light stock). Let sit until they are cool. Transfer the vegetables to the paper towel–lined sheet to dry. Let the cooking water cool and transfer to rigid containers to use as a vegetable stock. It will keep for up to 1 week in the refrigerator or 1 month in the freezer.
Dry the vegetables—Pat the vegetables all over to ensure they are completely dry; water on vegetables is the devil and will cause them to deteriorate quickly. Line a rigid storage container with paper towels and transfer the vegetables to it. Each time you use the vegetable, replace the paper towel to combat condensation, which is inevitable if the container sits on the counter and then goes back into the refrigerator.