How to Cook Vegetables in a Roaster Oven Without Burning Them

by M.T. Wroblewski

You wouldn’t be the first person who finally persuaded a finicky child to eat his or her vegetables by roasting them. Nor would you be the first person who was the hit at a potluck party because your crisp, roasted vegetables snapped and sizzled. There’s no doubt: roasted vegetables are an equal opportunity culinary hit. Despite the flavor advantages that roasting offers, some cooks are nervous about cooking vegetables in a roaster oven without burning them. But never fear. Although you may wish to take a conservative approach to your first roasting adventure, you can finesse your technique and become a pro roaster in no time.

Wash the vegetables and cut them into equal, bite-size pieces. Think about the size of a medium mushroom or a baby carrot and cut your vegetables accordingly so that they cook evenly.

Coat the vegetables with olive oil in one of two ways. You can drizzle olive oil on the pan, lay the vegetables inside and sprinkle the vegetables with salt and pepper. The vegetables will get coated on the other side when you turn them while they cook. Or you can put a little olive oil in a bowl, sprinkle the salt and pepper inside, add your vegetables and then toss thoroughly until the vegetables are fully coated. For either method, you can add marjoram, oregano or thyme – all of which will nicely endure a roasted temperature. But if you prefer basil, dill, parsley or rosemary, you should add them once the vegetables come out of the oven.

Place the vegetables in a single layer on the roasting pan so that they cook evenly. Ensure that they fit snugly but are not doubled-up or overlapping one another.

Set the temperature of your roaster oven to between 400 and 450 degrees Fahrenheit. If this is the first time you are cooking vegetables in a roaster oven, you might wish to make your first batch at the lower temperature and then, the next few times, raise the temperature by 25 degrees. In general, an oven set at 425 F is likely to produce caramelized vegetables while an oven set at 450 F will produce very crisp and brown vegetables. The higher temperatures also will reduce the cooking time. Starting at 400 F will result in a batch of vegetables that are crisp on the outside and tender on the outside – an ideal result.

Adjust your roasting time for the type of vegetables you’re roasting because some take longer to cook. Asparagus, green onions, mushrooms and tomatoes – the “soft” vegetables – should take between 10 and 20 minutes. Vegetables such as bell peppers, broccoli, cauliflower, eggplant, onions, squash and zucchini will take longer, from 15 to 30 minutes. Beets, Brussel sprouts, carrots, potatoes and turnips will take even longer, up to 45 minutes.

Stir the vegetables and flip them over in the roasting pan at the early end of the roasting time and judge how they’re doing. If they seem a bit dry, sprinkle them with a little water. Remove the vegetables when they’re fork-tender and nicely browned – but not blackened – on the outside. Season the vegetables, if you like, with your herb of choice. The hot olive oil will absorb the seasoning nicely.

Items you will need

  • Vegetables
  • Olive oil
  • Salt
  • Pepper
  • Seasonings (optional)


  • If you’re making a vegetable medley, with an assortment of slow-, medium- and fast-cooking vegetables, start the “slow cookers” first, then add the others to ensure a consistent finish.

About the Author

With education, health care and small business marketing as her core interests, M.T. Wroblewski has penned pieces for Woman's Day, Family Circle, Ladies Home Journal and many newspapers and magazines. She holds a master's degree in journalism from Northern Illinois University.

Photo Credits

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