Roasted Cauliflower and Onion Soup with Gruyere
A low-carb take on French onion soup using roasted cauliflower and sweet caramelized onions as the base. Garlic cloves roast alongside vegetables to develop deep, savory flavor, then simmer into a rich, satisfying broth finished with melted cheese. Serve as a light lunch or elegant starter; works year-round but especially warming in cooler months. This version trades traditional bread thickening for cauliflower's natural body while keeping the indulgent cheese topping.
Ingredients
Instructions
- 1
Preheat oven to 375°F (conventional) or 350°F (fan assisted).
- 2
Chop cauliflower into florets and slice onions.
- 3
Toss vegetables with garlic cloves, olive oil, salt and pepper in roasting dish.
- 4
Roast for about 45 minutes, stirring halfway through, until browned.
- 5
Transfer roasted vegetables to pot with stock and water.
- 6
Squeeze roasted garlic from skins into pot.
- 7
Bring to simmer and cook about 10 minutes.
- 8
Serve topped with grated cheese.
Tips
Don't skip the halfway stir during roasting. This ensures even browning and prevents burnt spots that can turn bitter.
Squeeze garlic gently from cooled skins; a small slit helps. The cloves turn creamy and mild after roasting.
Good to Know
Refrigerate in airtight container up to 5 days. Freeze up to 3 months.
Make through step 6 and refrigerate up to 2 days. Simmer fresh before serving to preserve texture.
Ladle into bowls, top with grated cheese. Pair with a simple green salad or crusty bread for non-low-carb guests.
Common Mistakes
Stir vegetables only once during roasting to avoid Y: vegetables stay pale and lack caramelization.
Substitutions
Dairy-Free Swaps
General Alternatives
FAQ
Can I blend this soup smooth?
Yes. After simmering, transfer to blender in batches or use immersion blender for 1-2 minutes. Texture becomes creamy while keeping the low-carb profile. Do not over-blend; some vegetable texture adds body.
What if my vegetables aren't browned after 45 minutes?
Oven temps vary. Add 5-10 minutes and stir. If oven runs cool, increase to 200C. Browning matters for depth of flavor; don't skip this step.
How long does frozen soup keep and how do I reheat?
Frozen soup keeps 3 months. Thaw overnight in fridge or reheat from frozen on stovetop over medium heat for 15-20 minutes, stirring often. Add cheese after reheating.