Mary Berry Parmentier Potatoes

I used to think roast potatoes were the ultimate side dish—until I made Mary’s Parmentier potatoes. These little golden cubes are like the fancier, French cousin of a classic roastie: crisp on the outside, buttery soft in the middle, and totally packed with flavour thanks to garlic, thyme, and sweet roasted onion.

The first time I made them, I overcrowded the tray and ended up with… well, a very soft potato casserole. Tasty, but not quite what we were going for. Lesson learned. Now I give them space, I use baking paper (trust me on this), and they come out like little golden nuggets of joy—every time.

Why This One Works So Well

Boiling the potatoes briefly before roasting means you’re halfway to creamy middles before they even hit the oven. Tossing them in garlic-thyme butter after boiling lets the flavour soak in rather than just sitting on the surface. And roasting with onion? It brings out this lovely caramelised sweetness that plays beautifully with the savoury herbs. It’s a classic Mary move—simple steps that make everything taste better.

INGREDIENTS + WHY THEY MATTER

• Potatoes (1.5kg) – I’ve used Maris Piper, King Edward, and even Charlotte potatoes. The key is a waxy or all-purpose potato that holds its shape.
• Onion (1, chopped) – Don’t skip it. It softens and sweetens as it roasts, adding gorgeous flavour.
• Butter (100g, melted) – For flavour and crisping. I’ve tried olive oil—good, but butter wins.
• Fresh Thyme (2 tbsp) – Earthy and aromatic. Dried thyme works in a pinch, but use half as much.
• Garlic (2 cloves, crushed) – Infuses the butter and adds warmth. Don’t use jarred—it can taste sharp.
• Salt & Black Pepper – Generously season the water and before roasting. Under-seasoned potatoes are a crime.

Making It Yours (Without Ruining It)

• Try Ghee or Duck Fat: For a richer, deeper flavour, ghee or duck fat make them even crispier.
• Cheesy Finish: Sprinkle over grated Parmesan or Cheddar in the last 5 minutes of roasting for a savoury crust.
• Herb Variations: Rosemary, sage, or even a bit of oregano work beautifully here.
• Add Heat: A pinch of smoked paprika or a dusting of cayenne gives these a gentle kick.

MISTAKES I’VE MADE (AND HOW TO AVOID THEM)

What Went Wrong	Why It Happens	How to Fix It
Mushy potatoes	Overboiled or used floury type	Boil just until starting to soften (5 mins max)
Didn’t crisp properly	Overcrowded tray or too much moisture	Spread in a single layer, let steam escape
Bland result	Didn’t season water or butter	Season early and generously
Garlic burnt	Used raw garlic on tray	Mix garlic into butter, not directly on tray

HOW TO MAKE MARY BERRY’S PARMENTIER POTATOES

1. Preheat + Prep – Set oven to 220°C/Fan 200°C/Gas 7. Line a large baking tray with non-stick parchment.
2. Cube the Potatoes – Peel and cut into 2cm chunks. Try to keep them uniform for even cooking.
3. Parboil with Onion – Cover with salted water. Bring to a boil, then add onion and boil for 5 mins. Drain well.
4. Toss in Flavour – Return potatoes and onion to the pot. Add melted butter, garlic, and thyme. Toss gently until coated. Season well.
5. Roast – Tip onto the baking tray in a single layer. Roast for 45 mins, turning halfway, until golden and crisp.
6. Serve – Hot, straight from the oven. Add a little fresh thyme if you’re feeling fancy.

TIPS FROM MY KITCHEN

• Let the potatoes steam dry in the colander for 2–3 mins before tossing in butter—helps them crisp.
• I use two trays if needed—crowded potatoes = soggy bottoms.
• For a festive version, I add chopped rosemary and orange zest in the last 10 minutes.
• If you love caramelised onions, add a second chopped onion and let them go golden alongside the potatoes.

STORAGE + REHEATING

• Fridge: Cool fully and store in a sealed container up to 3 days.
• Freezer: Freeze flat on a tray, then transfer to a bag. Keeps for 1 month.
• Reheat: Oven at 180°C for 10–15 mins until hot and crisp again. Avoid microwaving—they’ll go soft.

FREQUENTLY ASKED QUESTIONS

Q: Can I make these ahead of time?
A: Yes—parboil and toss in butter/herbs, then chill. Roast fresh on the day.

Q: What potatoes work best?
A: Maris Piper or Charlotte are ideal. Avoid very floury types—they fall apart.

Q: Can I use dried herbs?
A: Yes, but use less—about 1 tsp dried thyme. It’s stronger than fresh.

Q: Do I need to boil the potatoes first?
A: You can skip it, but you won’t get that soft middle. Parboiling is worth it.

Q: What should I serve with these?
A: Roasted chicken, grilled lamb, sausages, or even as a brunch side with eggs and spinach.

Try More Recipes:

• Mary Berry Roast Potatoes
• Mary Berry Mini Dauphinoise Potatoes
• Mary Berry Posh Jacket Potatoes