Roasting is the technique that converts vegetable skeptics. Someone who claims they don't like broccoli has likely only eaten it steamed or boiled. That same broccoli, roasted at high heat until the edges are dark and crispy and the interior is tender — that's an entirely different experience. Roasting concentrates sugars, develops new flavor compounds through caramelization and Maillard reactions, and creates textural contrast that makes vegetables genuinely craveable.
The Foundational Principles
High Heat is Essential
The minimum for good roasting is 400°F (205°C). Most vegetables do best at 425-450°F (220-230°C). Lower temperatures produce steaming rather than roasting — everything turns soft without developing color or flavor. The high heat is what drives the caramelization.
Dry Before You Oil
Wet vegetables steam instead of roast. Pat vegetables dry after washing. Any moisture on the surface will convert to steam in the oven, slowing caramelization. This is especially important for mushrooms (naturally high moisture) and zucchini.
Don't Crowd the Pan
Leave space between pieces. Crowded vegetables create a humid microenvironment and steam each other. A single layer with space between each piece is non-negotiable for proper roasting. Use two sheet pans if needed.
Cut Uniformly
Pieces should be roughly the same size so they cook at the same rate. If pieces vary dramatically in size, smaller pieces burn before larger ones cook through.
The Roasting Formula
- Toss vegetables with 2-3 tablespoons of oil per sheet pan
- Season generously with salt and pepper
- Spread in a single layer on a sheet pan (lined with parchment for easy cleanup)
- Roast at 425°F without disturbing for 15-20 minutes
- Flip once, then continue roasting until done
Timing Guide by Vegetable
- Cherry tomatoes: 15-20 min at 400°F — blister and burst into sweet, jammy bites
- Asparagus: 10-15 min at 425°F — thin spears; roll in oil, season, roast at high heat
- Broccoli and cauliflower: 20-25 min at 425°F — cut into florets; edges should be dark
- Brussels sprouts: 20-25 min at 425°F — halve them; flat sides against the pan for good browning
- Root vegetables (carrots, parsnips, beets): 35-45 min at 400°F — cut 1-inch pieces; they need time
- Sweet potato: 25-30 min at 425°F — cubes; toss with oil and smoked paprika
- Bell peppers: 25-30 min at 425°F — strips or halves; they'll char beautifully
- Zucchini and eggplant: 20-25 min at 425°F — salt and rest 15 min first to draw out moisture
Finishing Touches That Elevate
After roasting, while still hot:
- A drizzle of good olive oil
- Lemon juice and zest
- Fresh herbs — parsley, basil, mint, tarragon
- Grated Parmesan
- Pomegranate molasses on roasted root vegetables
- Tahini drizzle on roasted cauliflower
- Balsamic glaze on roasted Brussels sprouts
- Crumbled goat cheese on roasted beets
💡 Roasting Tips
- Always roast on the lower rack for better bottom browning
- Parchment paper makes cleanup effortless and prevents sticking
- Don't move vegetables too often — they need contact time with the hot pan
- Roasted vegetables can be made in advance and used throughout the week — they reheat well
- Season generously — roasting concentrates flavor but also concentrates saltiness, so taste after roasting