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Pre-cooking certain vegetables before placing them on the grill can significantly reduce preparation time and ensure more even cooking. If your goal is to halve the cooking time of grilled vegetables, this trick is especially useful for tough or compact vegetables, such as potatoes, carrots, fennel, and cauliflower, which risk burning on the surface before becoming tender inside.
Blanching isn't necessary for all vegetables, however, and it doesn't always guarantee exactly half the cooking time. Zucchini, eggplant, tomatoes, and peppers, for example, can be grilled directly if cut correctly. The method should therefore be chosen based on the vegetable's texture and the desired result.
Which vegetables are best to blanch?
Precooking is especially recommended for vegetables that require a long cooking time. Potatoes, carrots, celeriac, cauliflower, broccoli, fennel, and corn on the cob can be immersed in boiling water for a few minutes before grilling.
The goal isn't to cook them completely, but to slightly soften their fibers. The inside should still be firm, as it will finish cooking under the direct heat of the grill.
Potatoes can be blanched whole, if small, or already cut into thick slices. Carrots and fennel should be cut into evenly sized pieces, while cauliflower and broccoli can be separated into florets large enough to avoid breaking during cooking.
The cooking time varies depending on the size and consistency. Generally, a few minutes are enough, checking with the tip of a knife: it should just fit, still meeting some resistance.
Which vegetables do not require pre-cooking?
Zucchini and eggplant have flesh that softens quickly. They can be sliced and grilled directly, without blanching. Boiling them in water would easily make them too soft and could prevent the characteristic golden streaks from forming.
Sliced onions, firm tomatoes, thin asparagus, and mushrooms can also be grilled directly. Very large asparagus, however, can benefit from a brief pre-cooking in steam or water.
Peppers don't necessarily need to be baked first. They can be cooked directly on the grill, whole or sliced. Baking before grilling would reduce the time spent on the grill, but would increase the overall cooking time.
How to blanch vegetables properly
Vegetables should be cleaned and cut into uniformly sized pieces. This way, they will be cooked to the same degree and you won't need to remove some pieces while others are still tough.
Bring a pot of water, lightly salted if desired, to a boil, then add the vegetables. It's best not to overfill the pot, as too much will lower the water temperature.
After a few minutes, check the consistency. The vegetables should be slightly softened but still firm. Overcooking them will make them brittle, difficult to turn, and prone to falling apart on the grill.
Once drained, they can be cooled briefly in very cold water, especially if they aren't being grilled immediately. This step stops the cooking process and helps some green vegetables retain a brighter color.
Dry them before grilling them
After blanching, vegetables must be dried very carefully. Any water left on the surface produces steam, hinders browning, and can cause splattering when it comes into contact with a greased griddle.
The vegetables can be spread out on a clean cloth or paper towel and gently patted dry. Before seasoning, they should be dry, even in the creases and between the florets.
This step is essential for obtaining a well-grilled surface. Wet vegetables tend to boil over, becoming soft without developing the aromatic notes typical of high-temperature cooking.
How to season before grilling
Dry vegetables can be brushed with a light drizzle of extra virgin olive oil. It's not necessary to use a generous amount: too much oil could drip onto the coals, create smoke, and mask the vegetables' natural flavor.
Salt can be added before or after cooking. For eggplant and zucchini, adding salt well in advance draws water from the flesh; for a perfectly dry surface, it's best to season them shortly before grilling or directly afterward.
Delicate herbs, such as basil and parsley, should be added after cooking to prevent burning. Rosemary, thyme, and sage tolerate heat better, but should still be used sparingly.
Temperature and grill placement
The grill or griddle must be very hot before adding the vegetables. An underheated surface will prolong cooking and may cause them to absorb more oil.
The vegetables should be arranged without overlapping, leaving a small space between each piece. They shouldn't be moved continuously; it's best to wait until the streaks have formed before turning them.
Blanched vegetables only need the time needed to finish cooking and brown the surface. Once tender, they should be removed from the heat immediately to prevent them from becoming mushy.
Alternatives to blanching
Steaming is a good alternative because it tenderizes vegetables without immersing them in water. It's particularly suitable for broccoli, cauliflower, carrots, and potatoes.
The microwave can also speed up preparation. Cut vegetables can be cooked for a few minutes in a suitable container with a small amount of water, then dried and transferred to the grill.
These methods help limit the loss of some water-soluble substances. However, it's incorrect to say that blanching always preserves all nutritional properties better: some heat-sensitive or soluble nutrients may be lost during any precooking process.
How to prepare an even grill
When grilling different vegetables, it's helpful to divide them according to cooking time. Tougher vegetables should be pre-cooked or added first, while zucchini, tomatoes, and mushrooms can be added later.
The thickness of the cut is also important. Slices that are too thin burn quickly and can dry out; pieces that are too thick risk remaining tough in the center. A regular cut ensures more predictable cooking and a neat presentation.
In conclusion
Blanching vegetables before grilling them can significantly reduce grilling time, especially for potatoes, carrots, fennel, and cauliflower. Precooking should be brief and leave the vegetables still firm.
Zucchini, eggplant, peppers, and other tender vegetables can be grilled directly. Drying each piece thoroughly, using a little oil, and grilling on a preheated grill will ensure the vegetables are tender on the inside, golden brown on the outside, and free of excess moisture.
