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Potato/ Sides

French Onion Boulangere Potatoes

December 17, 2023 (Last Updated: December 25, 2023) by Chris Collins

This has to be one of the most delicious potato side dishes in the world!

Boulangere potatoes are very similar to Dauphinoise Potatoes, only they’re cooked in stock and often with onions. Here I’m taking things to new heights by doing a French onion twist! Follow me…

close up shot of spatula lifting french onion boulangere potatoes from baking dish

Caramelized Onions

These are a key ingredient in French onion soup. They also add a gorgeous sweetness to this dish, which is otherwise rich and beefy.

Low ‘n’ Slow

The aim of the game for caramelizing onions is to fry them fairly low and slow. You want to tickle out the natural sugars and have them caramelize in the pan. If the heat is too high the onions are going to cook too quickly and you’ll just end up with regular fried onions.

Can I make these ahead of time?

Absolutely! I often do these the day before, just to get the most timely part out of the way. Just cool and tightly store until needed.

Process shots: add oil and butter to pan (photo 1), fry onion (photo 2), season (photo 3), caramelize then fry garlic and thyme (photo 4).

4 step by step photos showing how to caramelize onions

Sliced Potatoes Boulangere

How to slice Boulangere potatoes?

I usually go for the trusty sharp knife and chopping board, but you can use a mandoline if you’d prefer.  If slicing with a knife, I find it easiest to slice off the base of the potato, just to stabilise as you chop. In both cases you want them very thin – around 1/8″ / 3mm. You also want to ensure the slices are even, so they all cook at an even rate.

Process shots: peel potatoes (photo 1), thinly slice (photo 2).

2 step by step photos showing how to slice potatoes boulangere

Boulangere Potatoes

The final component is the stock. Typically it seems you’d use vegetable stock, but I prefer using beef. Not only is this the classic option for French onion soup, but it offers much more depth of flavour. Instead of regular beef stock, we’re going to spruce it up a little, just to really enhance the dish. Here’s what you’ll need:

  • Beef stock – the best quality you can find.
  • Worcestershire sauce – for a boost of flavour.
  • Beef Oxo/Bouillon cubes – these really deepen the flavour of the stock and turn it extra rich, beefy and salty (needs to be salty as the potatoes soak in so much!)
  • Cornflour/Cornstarch – this will help thicken the stock to a gravy consistency, which works amazingly in this dish. I find they can come out a little watery if you’re just using stock.

Just whisk and simmer those ingredients for 15 minutes until the stock thickens. It’ll be very rich and salty at this point, but as I mentioned, potatoes soak in so much flavour/seasoning so it needs to be.

To stack the boulangere, just layer the potatoes with the onions and stock, finish with some tiny cubes of butter. From there, we’re going to slowly bake it until knife tender, then finish with some Gruyere under the grill!

Process shots: layer potatoes and season (photo 1), top with onions (photo 2), top with stock (photo 3), repeat then add butter (photo 4), bake (photo 5), top with cheese and grill (photo 6).

6 step by step photos showing how to make boulangere potatoes

Potatoes Boulangere FAQ

What kind of potatoes should I use?

I recommend floury potatoes such as Maris Pipers or Russets. The starch will help thicken the sauce and they tend to soften more easily as they bake. I find waxier potatoes don’t absorb the sauce quite as well.

Do I have to use Gruyere?

If you’ve not got Gruyere I’d go with some Swiss cheese. Failing that opt for Cheddar. If you don’t like cheese or can’t have it this is still delicious without!

Can I make this ahead of time?

I recommend doing this fresh if you can. Having said that you can make the whole thing then reheat (more on this in the recipe card below). Or you could prep the whole thing, just make sure the stock cools otherwise it’ll start cooking the potatoes.

close up shot of french onion potatoes fresh out the oven garnished with fresh thyme

Serving Boulangere Potatoes

These make the perfect Side Dish alongside things such as Roast Chicken, Sausages and Pies.

For more French onion inspired recipes check out my French Onion Mac and Cheese and French Onion Pork Chops!

Alrighty, let’s tuck into the full recipe for these Boulangere French Onion Potatoes shall we?!

french onion potatoes boulangere served on small white plate with pie and carrots

How to make French Onion Boulangere Potatoes (Full Recipe & Video)

close up shot of spatula lifting french onion boulangere potatoes from baking dish

French Onion Boulangere Potatoes

This has to be one of the most delicious potato side dishes in the world!
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Servings (click & slide): 6
Course: Side Dish
Cuisine: French
Prep Time: 20 minutes
Cook Time: 1 hour 50 minutes
Total Time: 2 hours 5 minutes
Calories per serving: 354kcal
Cost per serving: £1.50 / $2

Equipment:

  • Sharp Knife & Chopping Board
  • Large Non-Stick Pan & Wooden Spoon (for onions)
  • Medium-Sized Pot, Whisk & Jug (for stock)
  • Potato Peeler
  • 9" x 9" / 23cm x 23cm Baking Dish
  • Cheese Grater

Ingredients (check list):

Onions

  • 1 tbsp EACH: Olive Oil, Butter
  • 600g / 1.3lb White Onions, thinly sliced
  • 1/2 tsp Salt
  • 1/4 tsp Black Pepper
  • 2 large cloves of Garlic, finely diced
  • 2 tsp Fresh Thyme Leaves

Potatoes

  • 1kg / 2lb Maris Pipers/Russets, or other starchy/baking potato
  • 600ml / 2 1/2 cups Beef Stock
  • 2x Beef Oxo/Bouillon Cubes, crumbled
  • 1 tbsp Cornflour/Cornstarch
  • 1 tsp Worcestershire Sauce
  • 2 tbsp Butter
  • 120g / 4oz Gruyere, grated
  • Salt, as needed

Instructions:

  • Add 1 tbsp butter and oil to a large non-stick pan over medium heat. Add the onions and fry until they begin to soften and just about start to take on colour (around 15 minutes or so). Season with salt and pepper, then turn the heat to low and continue gently frying until very soft, deep golden and a little sticky (around 30-40 minutes). With a few minutes to go, stir in the garlic and thyme. The lower and slower you fry the onions the softer/more caramelized they'll be, so don't rush the process.
  • With around 15 minutes to go, add the stock to a medium-sized pot over medium heat. Stir in the Worcestershire sauce and Oxo cubes. In a small bowl or pot to one side, mix the cornflour with 1 tbsp cold water then whisk that into the stock. Gently simmer the stock for 15 minutes until it starts to thicken (you should be left with 450ml liquid).
  • During this time, peel and very thinly slice the potatoes (approx 1/8"). Grease the base of the baking dish with 1/2 tbsp butter and dice the rest into tiny cubes. Preheat the oven to 170C/340F.
  • Layer 1/5 of the potatoes in the dish, overlapping slightly as needed to prevent gaps. Season with a pinch of salt, then top with 1/4 of the onions. Drizzle over 1/5 of the stock, then repeat with the remaining layers (remember to season each layer - see notes). Finish with a drizzle of stock then scatter over the butter.
  • Bake uncovered in the oven for 70 minutes, or until knife tender right the way through. Top with gruyere then finish under the grill until deep golden and bubbly. Rest for 5-10 minutes to allow the potatoes to finish soaking in the stock, then slice into portions, serve up and enjoy!

Quick 1 min demo!

Notes:

a) Onions - Don't rush the process, it takes time to tickle out the natural sweetness from the onions to properly caramelize them. If at any point the onions start drying out or burning, just turn down the heat and consider adding a splash of water. This will also help scrape off any fond from the pan too. You can make these ahead of time, just allow to cool and tightly store in the fridge for up to a few days.
b) Salt - Potatoes soak up salt like there's no tomorrow, so whilst the stock will taste pretty rich and salty, it's needed. I typically end up using 1/4 tsp salt in total to season the individual layers.
c) Temp/Timings - You want to be on the safe side and bake for a longer time at a lower temp, just to full ensure the potatoes cook right through. Ovens are all slightly different too, so timings will vary slightly. If you find after around 45mins the potatoes are struggling to cook through then increase the temp slightly to 180C/350F. On the contrary, if you find the top is browning too quickly and the potatoes are too firm, just drop the temp slightly to 160C/320F.
d) Make Ahead/Storage - I do like to make these fresh, but you can make them ahead of time if you'd prefer. The potato just soaks up a fair bit of the stock as they rest and they don't come out quite as saucy. Still taste awesome though! Just cook as instructed then allow to completely cool and tightly store in the fridge for 3-4days. Cover in foil and reheat in the oven at 180C/350F for 30mins, or until bubbling hot through the centre. Can grill/broil the top again to crisp up if you want! Can reheat individual portions in the microwave for ease if you'd prefer.
e) Inspiration - Inspired by a recipe by Anna Glover.
f) Calories - whole recipe divided by 6.

Your Private Notes:

Nutrition:

Nutrition Facts
French Onion Boulangere Potatoes
Amount Per Serving
Calories 354 Calories from Fat 147
% Daily Value*
Fat 16.34g25%
Saturated Fat 8.775g44%
Trans Fat 0.234g
Polyunsaturated Fat 0.98g
Monounsaturated Fat 5.663g
Cholesterol 43mg14%
Sodium 449mg19%
Potassium 886mg25%
Carbohydrates 41.61g14%
Fiber 4g16%
Sugar 5.57g6%
Protein 12.27g25%
Vitamin A 433IU9%
Vitamin C 17.9mg22%
Calcium 305mg31%
Iron 1.88mg10%
* Percent Daily Values are based on a 2000 calorie diet.
Nutrition is based on the absence of salt unless stated as a measurement in the ingredients. Cost is worked out based on ingredients bought from UK supermarkets, then divided by the number of servings. In both instances these values are just for guidance. Please check out my FAQ Page for more info.
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2 Comments

  • Reply
    Rachel P
    December 30, 2023 at 7:22 pm

    Can yellow onions be used or should we stick to white?

    • Reply
      Chris Collins
      December 31, 2023 at 10:55 am

      Either should work fine 🙂 C.

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    DINNERS

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