Harissa Roasted Cauliflower

Veggies

• Cauliflower: You’ll need two very large whole cauliflowers or three medium-sized ones (large ones work best). Look for cauliflower with some of the outer leaves attached. And make sure your roasting tray has enough space to fit the cauliflower pieces in a single layer with space between them. To use cauliflower florets instead, increase the oven temperature and reduce the cooking time to avoid overcooking while allowing for ample browning of cauliflower florets. 
• Onions: The roasted onions add sweetness to the dish. You can use red or white onions. 

Harissa butter marinade

The harissa butter marinade adds a spicy and fragrant kick with caramelised brown butter vibes.

• Harissa paste: This North African red pepper paste is the key flavour of the marinade with its fragrant, spicy taste. If you can’t find harissa paste, you can make your own rose harissa paste from roasted bell peppers, or make quick and easy harissa from rehydrated chiles, or try a harissa paste substitute instead.
• Butter: I use unsalted butter in this recipe. But you can just as easily use salted butter. Simply adjust the amount of salt in the recipe to taste. And, for a vegan option, swap the butter for olive oil or try to use this vegan harissa dressing as a marinade instead.
• Tomato paste: If you don’t have tomato paste, substitute it with more harissa paste for a sweeter, spicier end result. 
• Olive oil: Use good quality extra-virgin olive oil for added richness and flavour. 
• Maple syrup: A touch of maple syrup boosts the natural sweetness and aids in caramelisation. If you prefer, you can omit it or substitute it with caster sugar. Or try it with hot honey for more heat.
• Garlic: Minced garlic adds savoury notes. If you don’t have fresh garlic, substitute it with two teaspoons of garlic powder. 
• Cumin: Adds a warm and earthy flavour to the dish. But you can omit it if you don’t have any – we have enough bold flavours going on.
• Lemon zest and lemon wedges: The zest adds a bright and citrusy flavour to the harissa butter marinade. And, finishing the dish with a squeeze of fresh lemon juice cuts through the richness of the butter.
• Aleppo chilli flakes: Adds a subtle heat to the dish. If you don’t have Aleppo chilli flakes, you can substitute it with regular chilli flakes or a pinch of cayenne pepper (or try another Aleppo pepper substitute). Or omit it if the harissa is spicy enough for your taste.
• Salt: I use kosher salt in the harissa butter marinade. And using coarse sea salt when blanching the cauliflower ensures that it is seasoned throughout. You can also use any salt and adjust the seasoning to taste. Sprinkle the finished dish with Maldon salt flakes if you have some.

Optional add-ins

While this cauliflower roast holds its own as a meat-free main meal or side dish, you can still bulk it up to feed a crowd.

• Red chillies: Do as Yotam Ottolenghi does and add eight fresh red chillies. Cut a vertical slit into each chilli and add it to the roasting tray with the cauliflower and onions. It creates a super spicy cauliflower roast.
• Chickpeas: Cauliflower, chickpeas, and harissa are great friends. Turn this indulgent, buttery cauliflower into a more substantial meal with a can of drained chickpeas. Add the chickpeas for the second half of the cook.
• Red bell peppers: Core and devein two red bell peppers and slice them into thick strips. Add them to the baking sheet for the full roasting time.

If you use these optional add-ins, ensure your roasting tray is large enough to fit everything in an even layer. Or spread the cauliflower over two trays.

How to make harissa roasted cauliflower (step-by-step)

Slow-roasting this cauliflower allows it to get buttery and caramelised. And while it needs some time in the oven to achieve the best results, it’s a deceivingly simple recipe. 

Have your buttery harissa cauliflower ready in six easy steps:

• Step 1: Prepare the vegetables
• Step 2: Blanch the cauliflower
• Step 3: Preheat the oven
• Step 4: Make the harissa marinade
• Step 5: Coat the vegetables
• Step 6: Roast the cauliflower

Step 1: Prepare the vegetables

Quarter cauliflowers lengthways, leaving the leaves on if available. Trim the leaves slightly to expose the cauliflower tops.

Cut each onion into six wedges.

Step 2: Blanch the cauliflower

Fill a large pot with salted water and bring to a rolling boil. I use roughly one tablespoon for every quart (litre) of water.

Blanch the cauliflower quarters for 2 minutes. Keep them submerged by gently pressing down with a spatula or top the cauliflower with a smaller pot’s lid. 

You may need to do this in two batches if your pot is not big enough to fit all the cauliflower.

Drain well in a colander.

Step 3: Preheat the oven

Preheat a conventional oven to 400 °F (200 °C). This is roughly equal to 360 °F (180 °C) in a convection oven (fan oven).

Step 4: Make the harissa butter

Combine the melted unsalted butter, olive oil, harissa paste, tomato paste, maple syrup, minced garlic, ground cumin, lemon zest, Aleppo chilli flakes, and salt in a medium-sized mixing bowl.

Step 5: Coat the vegetables

Coat each piece of cauliflower in the harissa butter marinade by swirling it in the mixing bowl and rubbing sauce into the crevices.

Arrange each cauliflower quarter with one cut side facing down on a parchment-lined baking sheet (with rim) in an evenly spaced single layer. Add the onion wedges between pieces of cauliflower.

Spoon any remaining harissa butter over the veggies.

Step 6: Roast the cauliflower

Place the sheet pan in the centre of the oven and roast the cauliflower for 30 minutes. Baste the cauliflower with the melted harissa butter from the roasting sheet.

Reduce the oven temperature to 370°F / 190°C (340°F / 170°C in a convection oven) and continue roasting for another 30-40 minutes, basting twice, until the cauliflower browns and leaves crisp up.

Transfer the cauliflower and onions to a serving platter or serving bowl – don’t worry if the large wedges fall apart a bit. Spoon over any remaining harissa butter and browned bits from the baking tray. 

Taste a small piece, and sprinkle with salt if needed (use Maldon salt flakes if you have any) and a generous grind of black pepper. Serve with lemon wedges on the side.