Sweet, jammy roasted garlic is one of the easiest hands-off cooking projects around. Take a couple heads of garlic, lop the tops off, drizzle with a little oil, parcel them up in foil, and pop the packet in the oven until the cloves are soft and sweet. As with garlic confit, roasting whole cloves of garlic transforms them into spreadable morsels, perfect for dimpling into focaccia dough, blending into dressings, or spreading on a piece of crusty bread. Unlike garlic confit, roasted garlic requires no peeling, a fraction of the amount of oil, and no baby-sitting a pot on the stovetop for hours.
The tried and true method of roasting garlic in a foil packet works just fine and is—most importantly—easy, so we’ve provided instructions for that approach. But I’m also offering a slightly more hands-on method that I picked up when working in restaurants, one that bridges the divide between traditional roasted garlic and garlic confit: oil-roasted garlic. For this version, garlic heads are also roasted in a hot oven, but instead of using a foil packet, they are cooked in a lidded ovenproof saucepan with an inch of oil.
Oil-roasted garlic gives you the same soft, sweet cloves you’d expect from regular roasted garlic, but with a little more Maillard browning, and you’re also rewarded with garlic oil that’s perfect for adding an extra layer of flavor to dressings and sauces, like a roasted garlic Caesar. Think of oil-roasted garlic as sped-up confit, just slightly more work than the foil-roasting method but with more payoff.
The recipe below provides instructions for both roasting methods, so you can decide which to use depending on your time and needs.
The Science of Roasted Garlic
The pungent aromas we commonly associate with garlic are caused by the formation of sulfur-containing compounds when garlic’s cell walls are damaged—whether by a blade, a pestle, or our teeth. Rupturing garlic cells releases alliinase, an enzyme that reacts with a compound called alliin to form a volatile molecule called allicin, which lends pesto, toum, and hummus that characteristic allium bite. There are a variety of ways to temper garlic’s flavor, and if you’re looking to tap into its natural sweetness, slowly cooking the cloves whole is the way to go.
We all know that cooked garlic has a much more mellow flavor than the raw stuff. As noted in the cookbook Cook’s Science, from America’s Test Kitchen, the alliinase enzyme that gets the allicin party started is deactivated when it reaches 140 degrees Fahrenheit (60°C), and “heat also converts the harsh aroma of raw garlic into milder-flavored compounds called polysulfides.” However, anyone who has ever taken a batch of fried garlic a little too dark during cooking, or set the flame too high when toasting sliced cloves for aglio e olio, knows that overcooking garlic until it’s more brown than golden makes it bitter and harsh. Roasting garlic in the oven lands you in the perfect middle ground, with whole cloves that are turned soft and sweet during cooking, as their natural sugars caramelize (kind of like with another favorite low-and-slow allium cooking project, caramelized onions).
The Keys to Foil-Roasted Garlic
The roasting process is very straightforward, but there are some minor details that will help you get consistent results.
Before bundling them in foil, do make sure to coat the garlic heads with some kind of fat—extra-virgin olive oil is always a good bet. Fat helps with browning, and without it, you’ll just be steaming garlic in foil. In side-by-side tests, I found that garlic cloves roasted without any fat were pallid, flat-tasting, and, even though they softened during cooking, they ended up with a fibrous texture, not the jammy one we’re after.
Make sure your foil packet is sealed tight. Roasting garlic follows the same principles of roasting beets. Seal them up in foil, and let the moisture content create a miniature steam oven environment. The term “roasted” is actually a bit of a misnomer here, seeing as we really need steam to do a lot of the heavy lifting, rather than the dry heat that is required to produce a burnished crust on a Sunday roast. If you just threw a naked head of garlic or a few beets in a hot oven, you’d be rewarded with dried out, leathery, burnt-vegetable jerky.
Finally, this may seem minor, but don’t set your garlic packets directly on a baking sheet or in a pan. Putting cloves in direct contact with a solid piece of conductive metal increases the risk that they will scorch, producing that acrid burnt garlic flavor mentioned earlier. Place the foil packets on a wire rack set in a rimmed baking sheet instead, and you’ll get evenly cooked garlic, no baby-sitting required. Sure, you could toss the packets directly on your oven rack, but if the foil springs a leak, you’ll be on oven cleanup duty, in good company.
The Keys to Oil-Roasted Garlic
There are some details specific to oil-roasted garlic that are worth going over.
Remove as much of the papery skins from the garlic heads as possible before roasting, so that they don’t end up in the oil, which you will then have to spend time straining later on.
You can use neutral vegetable oil, extra-virgin olive oil, or a combination of the two. We love the flavor combination of extra-virgin olive oil and garlic, but the garlic oil made with canola in our garlic fried rice recipe is equally delicious, and puts a way smaller dent in your grocery budget. I usually opt for a 50/50 blend for this method, which gives me a little background peppery bite from the olive oil, but doesn’t break the bank. Unlike confit, this method doesn’t require submerging the garlic in oil—an inch of oil in a small saucepan is plenty.
Flip the heads halfway through cooking. The garlic heads are placed cut side down when they first go into the oven, and are flipped halfway through, once they are golden brown. This ensures that the cloves don’t take on too much color, which in turn would make them bitter.
Can You Roast Garlic in the Microwave?
There are a number of recipes out there for a microwave shortcut to roasted garlic. We tested this method and were not impressed with the results. Microwaving heads of garlic produces steamed cloves that are soft, but also pallid and fibrous, with none of the sweetness of roasted or confit garlic. We’re all for using the microwave when it delivers the goods, but we value flavor over time savings, and therefore do not recommend using the microwave in this case.