This keto-friendly roasted Dijon cauliflower is bright, tangy and full of flavor from Dijon mustard and fresh lemon. It makes an excellent low‑carb side dish that can complement weeknight dinners or holiday meals.
If you love mustard, this recipe is a delight. The lemon adds a fresh lift that balances the mustard’s bite. I almost ate the whole dish straight from the oven after sampling a piece—this side can easily steal the show.

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What is Dijon Mustard?
Dijon mustard is a French-style mustard originating from Dijon in Burgundy. It has a smooth, creamy texture and a sharp, tangy flavor derived from brown or black mustard seeds combined with wine, wine vinegar, water and salt. It’s more pungent than typical yellow mustard and adds depth to savory dishes.
Ingredients for this recipe
Simple ingredients come together to make a flavorful roasted cauliflower.

- Cauliflower – one fresh head, firm and white, cut into florets.
- Dijon mustard – plain or wholegrain, about 2 tablespoons.
- Lemon – juice and grated zest from one lemon.
- Butter – unsalted, melted to make the sauce.
- Olive oil – to coat the florets for roasting.
- Salt & pepper – to taste.
- Fresh parsley – chopped, optional for garnish.
How to make keto roasted cauliflower
Roasting cauliflower brings out a nutty sweetness; the Dijon and lemon butter sauce amplifies those flavors for a bright, savory finish.

Roast the cauliflower florets until golden and just tender.

Toss the roasted florets with the Dijon-lemon butter sauce and return to the oven briefly to set the flavors.
Storage
Store leftovers in an airtight container in the refrigerator for 3–5 days.
Reheating
To reheat and retain some crispness, spread the cauliflower on a baking sheet and warm in a 350°F (175°C) oven until heated through. For a quicker option, microwave covered until warm, but the texture may soften more.

Recipe Tips
You can prepare the dish a few hours ahead and reheat before serving. The mustard-lemon sauce also works well spooned over roasted chicken or baked fish.
If you prefer, use the same mustard and lemon mixture to roast a whole head of cauliflower for a dramatic presentation.
More low carb side dish recipes to try
Try these complementary low‑carb vegetable sides for variety: Garlic Parmesan Roasted Broccoli, Roasted Fennel with Parmesan, or a Cheesy Zucchini Gratin.
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Dijon Mustard Roasted Cauliflower
Angela Coleby
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Ingredients
- 1 head cauliflower cut into florets
- 6 tablespoons butter
- 1 lemon juice & grated rind
- 2 tablespoons Dijon mustard (wholegrain preferable)
- 1 teaspoon salt
- ½ teaspoon black pepper
- 1 tablespoon fresh parsley, chopped optional (for garnish)
- 1 tablespoon olive oil
Instructions
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Preheat the oven to 200°C / 400°F.
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Place cauliflower florets on a baking tray, drizzle with olive oil and sprinkle with salt. Roast for 20–25 minutes until golden and tender.
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Transfer the roasted cauliflower to an ovenproof dish.
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Melt the butter in a small saucepan, then stir in the Dijon mustard, lemon juice and lemon zest until smooth.
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Spoon the mustard-lemon butter over the cauliflower and return to the oven for about 10 minutes to meld the flavors.
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Garnish with chopped parsley and serve warm or at room temperature.
Notes
Nutrition
The nutrition information is an estimate provided by an online calculator.
