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…
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.
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).
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).
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.
Serving Boulangere Potatoes
Alrighty, let’s tuck into the full recipe for these Boulangere French Onion Potatoes shall we?!
How to make French Onion Boulangere Potatoes (Full Recipe & Video)
French Onion Boulangere Potatoes
- 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):
- 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
- 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
- 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!
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