Roasted Yams with Piri Piri Sauce and Sweet Spiced Seeds

Roasted yams with piri piri sauce and sweet spiced seeds is the dish that will change how you think about this knobbly little winter vegetable. Roasted cut side down until caramelised and sticky, piled with a smoky piri piri sauce, then finished with sweet and spicy seeds for crunch. It is a total flavour bomb and it is on the table in under an hour. Let's cook!

Why These Roasted Yams Work

Cut side down is the whole technique. Halve them lengthways and lay that flat face against a hot tray. It is the difference between a yam that is merely cooked and one with sticky caramelised edges and a soft fluffy middle.

The sauce is roasted, not raw. Onion, garlic, oregano and a chargrilled pepper all go through the heat before they go in the blender, which is where the smoky depth comes from. A raw blitz would taste sharp and thin.

The yoghurt is what turns heat into flavour. Before it goes in, the sauce is fiercely spicy and one dimensional. Three tablespoons of yoghurt and a splash of vinegar and it becomes creamy, balanced and complex. That is the whole trick of the recipe.

The seeds take three minutes and change the dish. Honey, cumin, coriander, almonds and sunflower seeds bubbled in a pan and tipped onto paper to crisp. Without them it is roasted veg with sauce. With them it is a proper plate of food.

Yams are cheap and they are in season. A winter staple here and very good value, and this is the recipe that makes the absolute most of them.

Recipe Details

• Prep Time: 10 minutes
• Cook Time: 40 to 45 minutes
• Total Time: 50 to 55 minutes
• Serves: 2 as a side dish
• Difficulty: Easy
• Special Equipment: Air fryer (or oven), blender or stick blender

This piri piri sauce is one I used to make a lot when I was private cheffing in Switzerland, for one family in particular, so it has a dear place in my heart. The thing nobody warns you about is how it tastes at the halfway point. Blitz the roasted vegetables with the paprika and taste it then and it is genuinely fierce, hot and flat and a bit alarming. Do not throw it out and do not add more of anything to fix it. The yoghurt and the vinegar are the fix, and once they go in it turns into something else entirely. Taste it before and after and you will not believe it is the same sauce. As for the yams themselves, they are something I barely ate growing up in the UK and did not properly meet until I moved to New Zealand, and now I look forward to yam season every single year. If you have never cooked with them, buy some next time you see them.

Ingredients

For the Roasted Yams

• 8 yams, scrubbed and halved lengthways
• Olive oil, to coat
• Salt and freshly ground black pepper

For the Piri Piri Sauce

• 1 large chargrilled pepper from a jar, roughly chopped
• 1/2 onion, sliced
• 2 cloves garlic
• 1/2 tsp dried chilli flakes, or 1/4 tsp for less heat
• 1 tsp smoked paprika
• 10 fresh oregano leaves
• Olive oil, a glug
• Salt and freshly ground black pepper
• 3 tbsp natural yoghurt
• A good splash of vinegar, nectarine, apple cider or any fruity vinegar
• A small handful of fresh coriander

For the Sweet Spiced Seeds

• 1 tbsp olive oil
• 1 tbsp honey
• 1/2 tsp ground coriander
• 1/2 tsp ground cumin
• A pinch of salt
• 2 tbsp flaked almonds
• 2 tbsp sunflower seeds

How to Make Roasted Yams with Piri Piri Sauce

1. Preheat the oven: Heat your oven to 190C (170C fan / 375F / Gas Mark 5) and line a baking tray.
2. Roast the yams: Toss the halved yams in a generous glug of olive oil and season well with salt and pepper. Place cut side down on the lined tray and roast for 30 minutes. Check at 20 minutes. If they are already looking golden, turn the oven up to 200C (180C fan) for the last 10 minutes for extra colour. They are ready when tender all the way through and the cut sides are sticky and golden.
3. Roast the sauce vegetables: While the yams are in the oven, toss the onion, garlic and oregano leaves in a glug of olive oil and season. Add the chargrilled pepper. Roast in the air fryer at 200C for 5 to 7 minutes, then reduce to 180C for a further 5 to 8 minutes until the onion is soft. Alternatively roast in the oven alongside the yams for 15 to 20 minutes.
4. Make the piri piri sauce: Transfer the roasted vegetables to a blender, or use a stick blender. Add the smoked paprika, natural yoghurt, a good splash of vinegar and the fresh coriander. Blitz until smooth. Taste and adjust the seasoning. The yoghurt and vinegar balance the heat, so add more of either if you want it milder or tangier.
5. Make the sweet spiced seeds: Heat the olive oil and honey in a small frying pan over a medium heat. Add the ground coriander, cumin, salt, flaked almonds and sunflower seeds. Stir to coat and let it bubble for 2 to 3 minutes, stirring frequently, until the seeds and almonds are turning golden and the mixture smells toasty. Pour straight onto a sheet of baking paper and spread out to cool. They crisp up as they cool.
6. Serve: Pile the roasted yams onto a serving plate or board. Spoon over the piri piri sauce generously and scatter the sweet spiced seeds on top. Serve straight away.

Why You'll Love This Recipe

• A completely different way to eat yams: Roasting cut side down gives you sticky caramelised edges and a fluffy centre that is completely DELICIOUS
• That piri piri sauce: Smoky paprika, roasted peppers, chilli, garlic and a dollop of yoghurt to cool it down. A proper sauce with proper heat
• Sweet and spicy seeds for crunch: A quick stovetop seed mix that crisps up on baking paper and adds the most addictive crunch on top
• Seasonal and budget friendly: Yams are a winter staple in New Zealand and incredibly good value
• A vegetarian side that steals the show: The kind of side dish people ask about, and genuinely easy to pull off

Chef's Tips for Roasted Yams

Always roast yams cut side down: This is non-negotiable. Get that flat surface in direct contact with the hot tray. Roast them cut side up and you miss all of the sticky golden goodness.

Do not panic at the halfway taste: The sauce is meant to be fierce before the yoghurt goes in. Adding more of anything else at that point will only make it worse.

Get the seeds off the heat before they look done: They keep cooking in the residual heat of the pan and on the paper. Pull them off when they are just turning golden. A minute too long and they burn.

Do not crowd the tray: Yams packed together steam instead of roasting and you lose the caramelisation entirely. Give them room, or use two trays.

Adjust the chilli to your people: Half a teaspoon gives a proper kick. A quarter is plenty if you are feeding anyone sensitive to heat.

Use any fruity vinegar you have: Nectarine, apple cider, white wine or a good red wine vinegar all work. The vinegar brightens the sauce and stops it feeling heavy.

Scatter the seeds at the last second: The moment they hit warm yams and wet sauce they start to soften, and that crunch is half the point.

Substitutions & Variations

• No yams? Kumara works beautifully and is easy to find year round. Cut into halves or thick wedges and roast the same way
• No air fryer? Roast the sauce vegetables in the oven alongside the yams for 15 to 20 minutes
• No chargrilled peppers in a jar? Roast a fresh red pepper yourself, halved and brushed with oil, at 200C for 25 minutes until charred and soft
• No fresh coriander? Flat leaf parsley works. Different flavour, still delicious
• Make it vegan: Swap the natural yoghurt for a good coconut yoghurt. Slightly different flavour, same creaminess and balance
• Make it milder: Reduce the dried chilli to 1/4 tsp for a gentler, sweeter sauce

Storage

Best eaten fresh: The yams are at their best straight from the oven while the caramelised edges are still crisp and the seeds are crunchy.

Fridge: Store the yams and sauce separately in airtight containers for up to 2 days. Reheat the yams in the oven at 180C for 10 to 12 minutes to revive some of the caramelisation. The sauce keeps well as a dip or dressing through the week. Keep the seeds in a small jar at room temperature, where they stay crisp for 3 to 4 days.

Freezer: Not recommended for the assembled dish. The sauce freezes on its own for up to 1 month, defrosted overnight in the fridge and stirred well. The yams do not freeze well once cooked.

Avoid: Scattering the seeds on before you are ready to serve. They soften on contact with the warm yams and sauce and you lose the crunch.

Frequently Asked Questions

What do yams taste like? New Zealand yams, also called oca, have a slightly waxy, earthy flavour with a gentle tang when raw that disappears with cooking. Roasted, they become tender and naturally sweet with a nutty edge. They are nothing like the large orange yams in American recipes. Ours are much smaller and more delicate.

My yams are not caramelising, what do I do? Two things to check. Make sure they are cut side down, and make sure the oven was fully preheated before they went in. If they have had 30 minutes and still look pale, turn it up to 200C (180C fan) for another 10. A little extra olive oil helps too.

Can I double this recipe? Yes, easily. Double everything and use two trays for the yams so they are not crowded, because crowded yams steam rather than roast. The sauce and seed quantities double without any issue.

What if I do not have a blender? A stick blender works perfectly. With neither, chop the roasted vegetables very finely and whisk them together with the yoghurt, vinegar and spices. More rustic, just as good.

What do you serve with roasted yams and piri piri sauce? It is a side dish, so it is brilliant next to roast chicken, grilled lamb or a piece of white fish. It also holds its own as a light vegetarian lunch with a green salad and flatbread to mop up the sauce.

Can I use the piri piri sauce on other things? Absolutely. It is brilliant as a dip for roasted vegetables, drizzled over grilled chicken or fish, stirred through grain salads or spread in wraps. For a bigger batch, my Easy Piri Piri Sauce is the classic version.

Can I make the components ahead? Yes. The sauce keeps in the fridge for 3 to 4 days and the seeds in a jar for 3 to 4 days. The yams are best roasted fresh, but you can halve, oil and season them and keep them in the fridge for up to a day.

Why is my sauce so hot before the yoghurt? Because it is meant to be. Roasted chilli and paprika with nothing to soften them will always taste fierce. The yoghurt and vinegar are doing the balancing, so taste it only once they are in.

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Roasted Jerusalem Artichokes with Spinach and Herb Sauce - Fellow winter roots roasted until golden and served with a vibrant green herb sauce.

How to Make Homemade Fruit Vinegar - Where the fruity vinegar in this sauce comes from, made for nothing out of apple or quince scraps.

Roasted yams are one of those winter vegetables that deserve far more attention than they get, and this recipe makes a real case for them. The piri piri sauce brings heat and depth, the sweet spiced seeds bring crunch and sweetness, and the yams themselves, sticky and caramelised and tender, are the perfect base for all of it. Once you have made this it will become your go to way to eat yams every winter.

Enjoy!

Del x

Sticky caramelised yams under a smoky piri piri sauce, finished with sweet spiced seeds for crunch.