Here's a winning combination of keto roasted vegetables, topped with freshly grated parmesan and a few squeezes of lemon juice. You'll love your veggies with this one!

Roasting brings out the best in this low-carb vegetable medley. The roasted broccoli turns crispy-crunchy, while the red onion, bell pepper and grape tomatoes soften and caramelize, creating a delicious combination of flavors and textures. It's a favorite side dish around here.
These low-carb roasted vegetables can be paired with almost any protein, including chicken, beef, pork or fish. You can change up the veggies, too — you can skip the tomatoes, add asparagus or zucchini, or just prepare with broccoli and onion.
The preparation, which includes chopping and dressing the veggies in olive oil and seasoning, takes a little over 5 minutes. The vegetables, then, roast in the oven for about 20 minutes. It's an easy sheet-pan side dish for any night of the week.
Key Ingredients

Just a few notes on key ingredients:
- Broccoli: We use 3 cups of chopped broccoli, roughly 6 ounces. You'll want to chop the broccoli into florets that are roughly the same size, about an inch or more in size.
- Red bell pepper: We use red bell pepper since it's sweeter than other colors, but you could also use green, yellow or orange bell pepper. You'll chop into 1-inch chunks.
- Red onion: One of our favorite roasted veggies is red onion. We use half of a medium-size onion, which is roughly 1 and a half ounces. You'll chop into 1-inch chunks.
- Grape tomatoes: We love the texture the juicy grape tomatoes add. To keep carbs low, we simply use ⅓ cup.
- Garlic Powder: Just a half teaspoon to add a little garlic flavor.
- Parmesan: We use freshly grated parmesan in this recipe, but you can use store-bought grated parmesan as well.
- Lemon: We love to add a few squeezes of fresh lemon to brighten the flavor, but it's optional.
How to Roast Vegetables
STEP 1: Pre-heat the oven to 400 degrees F. Cut the broccoli, bell pepper and red onion into similar-size chunks, about one or one and a half inches in size. (Note: you'll leave the grape tomatoes whole).
STEP 2: Line a rimmed baking sheet with tinfoil. Place the grape tomatoes and chopped broccoli, bell pepper and onion on a baking sheet. Gently toss with olive oil, garlic powder, salt and pepper. Spread vegetables evenly across pan so they are not touching on another. Roast in the oven for 10 minutes.


STEP 3: At 10 minutes, flip the vegetables and continuing roasting for 10 to 12 minutes. When done, the broccoli, bell pepper and onion should be tender and lightly charred. The grape tomatoes should be wilted with juices oozing.
STEP 4. Remove baking sheet from oven and top with grated parmesan and a few squeezes of lemon juice (if desired). Plate and serve.


Other Low Carb Vegetables for Roasting
You can change up the vegetables in this recipe and use other low-carb vegetables if you like. Here are some other low-carb vegetables that roast in about 20 minutes at 400 degrees F:
- Asparagus: Asparagus is low in carbs at roughly 1 net carb per cup. Simply snap the asparagus spears at their natural breaking point and dress with olive oil and seasoning and roast for about 20 minutes (or slightly less depending on thickness of spears).
- Zucchini: Zucchini is also low in carbs at roughly 1.5 net carbs per half cup. To roast, trim the ends off a small zucchini and slice into ½-inch thick rounds. Dress with olive oil and seasoning and roast for 20 minutes (flipping half way between).
- Cauliflower: Cauliflower is roughly 3 net carbs per cup. To roast, chop the cauliflower into 1-inch florets, dress with olive oil and seasoning, and roast for 20 minutes or slightly more (flipping half way between).
Related Recipes
Recipe

Keto Roasted Vegetables with Grated Parmesan
Ingredients
- 3 cups broccoli (roughly 6 ounces), chopped into 1-inch (or slightly more) florets
- 1 medium-size red bell pepper (roughly 4 ounces), ribs and seeds removed and cut into 1-inch (or slighly more) squares or rectangles
- ½ red onion (roughly 2 ounces), chopped into 1-inch chuncks
- ⅓ cup grape tomatoes (roughly 2.5 ounces)
- 2 tablespoons extra-virgin olive oil
- ½ teaspoon garlic powder
- ¼ teaspoon salt and ground pepper
- 3 tablespoons grated parmesan
- 1 to 2 teaspoons squeezed lemon juice (optional)
Instructions
- Get started: Pre-heat oven to 400 degrees F. Cut the broccoli, bell pepper and red onion into similar-size chunks, about one or one and a half inches in size. (Note: you'll leave the grape tomatoes whole).
- Prepare vegetables on baking sheet: Line a rimmed baking sheet with tinfoil. Place the grape tomatoes and chopped broccoli, bell pepper and onion on a baking sheet. Gently toss with olive oil, garlic powder, salt and pepper. Spread vegetables evenly across pan so they are not touching on another.
- Roast: Roast in the oven for 20 or more minutes. At 10 minutes, flip the vegetables and continue roasting for 10 to 12 minutes. When done, the broccoli, bell pepper and onion should be tender and lightly charred. The grape tomatoes should be wilted with juices oozing.
- Finish: Remove baking sheet from oven and top with grated parmesan and a few squeezes of lemon juice (if desired). Plate and serve.
Leave a Comment