The best cooking tip I’ve been lucky enough to ever receive came from a pastry chef, who has been a nearly life-long vegetarian. Strangely, this technique involves meat and not dessert.
I was eating dinner at her home, which included the most delicious roasted vegetables; I asked how she does it. Her elegant answer: “I’ve never understood why people don’t treat vegetables like meat.” After prodding for elaboration, I got the secret: get your pan screaming hot before adding anything to it.
A nice, browned, crisp sear is one of the best parts of eating meat, vegetables, bread, and pretty much anything else. This browning is known as the Maillard reaction that happens between amino acids and sugar as they are heated. Science was never my strong subject in school, so you can find more comprehensive explanations here or here or in Harold McGee’s excellent On Food and Cooking. The important thing to know is that browning and caramelization—the process that forms a crust—is what makes cooked food taste great.
When cooking meat, searing the outside is a crucial step (whether you do this first or last is an entirely different debate). You have to be patient and get your pan, grill, or broiler as hot as possible. Have you ever put a steak in a lukewarm pan? If so, it’s a mistake you only make once. The low temperature can even steam the food, which is the opposite of what you want. It only leads to disappointment.
So why put your chopped vegetables in a cold pan and stick in the oven? Why deny yourself even more caramelized, browned sides of potatoes, beets, or even asparagus? Why have mediocre roasted vegetables when you can have sublime roasted vegetables? (Have I made my case yet?)
Once you’ve seen the light, there’s the one two-second step that makes all the difference: As soon as you turn on your oven—425° to 450° is best for roasting most—stick a sheet pan or two in to heat up with the oven. After you’ve done that, proceed with cleaning, peeling, chopping, and whatever you need to do to get the vegetables ready. By the time the oven is up to temperature, your pan will be “ripping” (as chefs like to say), and when you spread the chopped vegetables into the pan, you’ll hear the very satisfying sound of searing. Then continue to roast the vegetables as you normally would: undisturbed for 20 to 25 minutes, then start checking and when the crust forms and the vegetables release from the pan, stirring every 10 minutes until they are roasted to your satisfaction.
Last weekend, I proved my friend’s theory. I found some very adorable fingerling sweet potatoes at the market. After dutifully heating my pan, I dumped the halved potatoes on, and quickly used my jumbo tweezers (pictured) to turn the cut surface down on each piece. They were exquisite.