How to Roast Vegetables

This post is adapted from the Preparing Local Vegetables workshop.  Warm, hearty comfort food can also be healthy and locally grown. Roasting different combinations of vegetables and changing up their seasonings are ways to make the most of what is available locally all winter long.

Roasting vegetables brings out their rich, deep flavours and creates delicious textures, like root vegetables that are crispy on the outside and soft inside. It is a healthier alternative to frying foods and highlights the flavour of vegetables more than boiling them does. Roasting can be substituted as a method in many recipes.

Different vegetables have different roasting times. When roasting multiple types of vegetables, follow one of these methods to ensure that they are all cooked properly:

  1. Roast each kind of vegetable separately and then mix them together before serving; or
  2. Cook multiple kinds of vegetable together starting with the ones that have longer roasting times and then adding the shorter-roasting ones to the pan later on; or
  3. Roast several vegetables together but choose combinations with similar cooking times so they will all be done at once. For example, butternut squash and fennel have similar roasting times to each other, as do green beans and asparagus.

The following are tips for successfully roasting vegetables:

  • Use a pre-heated hot oven to get vegetables that are crispy on the outside and cooked through.
  • Cut pieces to be about the same size so that they cook in the same amount of time.
  • Put a layer of parchment paper on the pan before roasting so that the vegetables don’t stick.
  • “If the vegetable pieces cover the pan sparsely, arrange them more toward the edges of the pan. Pieces near the edge brown better” (The Best of Fine Cooking: Roasting, 2009).

To Roast Vegetables

Step 1 – Prep the oven: Place the oven rack in the middle. Preheat the oven according to the chart below.

Step 2 – Prep the vegetables: In a large bowl pour about 1-3 tablespoons of olive or canola oil into the bottom; this allows you to know exactly how much oil you are using rather than drizzling oil on top and possibly using too much. Put the vegetable pieces into the bowl and toss them with the oil to lightly coat them. Season the vegetables with any herbs or spices you prefer. Letting them marinate for an hour or more in the fridge before roasting will help bring out flavours.

Step 3 – Roast the vegetables: Spread the vegetables out in a single layer on a cookie sheet or other pan that has an edge to keep juices in. Choose a pan that is shallow so that the vegetables can still crisp up. Allow the vegetables to roast for the required amount of time, flipping them as needed to keep them from overcooking on one side.

The following chart is adapted from The Best of Fine Cooking: Roasting (p.78-79). Rinse or scrub all vegetables before roasting. Peel them as desired; many vegetables are fine with the skins left on. Preheat the oven fully before putting vegetables in.

Vegetable

Servings/lb

Preparation

Roasting Instructions

Asparagus 3-4 Snap off tough bottom ends Roast at 475°F for 5 min, flip, roast until tender and a bit shriveled 5-8 min
Beets 4 Peel and cut into 1 inch wedges Roast at 475°F for 15 min, flip, roast until tender 10-15 min
Broccoli 2-3 Cut stem into 1/4 inch discs. Split the florets to 1-2 inches wide. Roast at 475°F for 8-10 min until floret tops begin to brown. Stir and roast until tender 3-6 min
Brussels sprouts 3-4 Trim stems off. Cut in half lengthwise. Put on pan cut side down. Roast at 475°F for 15 min until tender and browned. No need to flip.
Carrots 3-4 Cut into like-sized pieces or strips Roast at 475°F for 12-15 min until bottoms lightly brown, flip, roast until tender and slightly shriveled 3-5 min
Cauliflower 3-4 Split florets to 1-2 inches wide. Roast at 475°F, stirring every 10 min, until tender and lightly browned, 20-25 min total
Celery root 2 servings per root Trim and peel. Cut into 1 inch pieces. Roast at 425°F for 30 min, flip, lower heat to 375°F and roast for an additional 30 min.
Fennel 3-4 Quarter lengthwise then cut into 1 inch wedges Roast at 475°F for 15 min until pieces begin to brown on the edges, flip, roast until tender and browned 10 min
Garlic 2 servings per bulb Peel off outer layers of bulb, leaving skins of cloves intact. Cut off 1/4 inch from top of cloves to expose them inside skins. Drizzle olive oil lightly onto clove tops. Cover with tinfoil in a muffin tin. Roast at 400°F until soft 30-35 min
Green beans 4 Trim stems Roast at 475°F for 15 min until tender, a bit shriveled, and slightly browned. No need to flip.
Kohlrabi bulb 1 serving per bulb Cut in half crosswise. Cut into 1/4 inch thick wedges. Roast 450°F 15-20 min until browned, flipping occasionally
Mushrooms 3-4 Trim stems off if desired. Or cut in half lengthwise. Roast at 475°F for 20-25 min with trimmed or cut side down, flip, and roast until browned on top 5-10 min.
Onions 2 servings per medium sized onion Peel off papery outer layers. Cut in half crosswise. Cut into wedges if desired. Roast at 425°F cut side down 25-30 min until browned and tender
Parsnips 2-3 Cut in half crosswise. Cut thicker pieces in half lengthwise. Cut all crosswise into 2 inch lengths. Roast at 475°F for 10 min until browned on bottom, flip, roast until tender 5 min
Potatoes 2-3 Cut into 1 inch pieces Roast at 475°F for 10-15 min until browned on bottom, flip, roast until tender 5 min
Rutabaga 3-4 Cut into 1/2 to 3/4 inch pieces Roast at 475°F for 13-15 min until browned on bottom, flip, roast until tender 5 min
Tomatoes   Cut in half and remove seeds and pulp for larger tomatoes. Leave cherry tomatoes whole with seeds. Roast cut side up at 400°F 25-45 min depending on size, until browned and slightly shriveled.
Turnips 3-4 Cut into 3/4 to 1 inch pieces Roast at 475°F for 10-15 min until browned on bottom, flip, roast until tender 5 minutes
Winter squash- pieces (E.g. butternut, buttercup, acorn, pumpkin, etc.) 4 Peel and cut into 3/4 to 1 inch pieces. Roast at 475°F for 15 min until browned on bottom, flip and roast until tender 5-10 min
Winter squash- halves   Cut squash in half lengthwise. Scoop out all the seeds and pulp. Roast cut side down at 350ºF with 1/4 cup water poured into the pan. Squash is done when tender, skin slightly browned, and a fork can be inserted into flesh easily.
Summer squash (zucchini, white and yellow summer squash) 4-6 Trim top and bottom off. Quarter lengthwise and cut into 2 inch long wedges Roast at 450°F skin side down 5-10 min until browned