French Onion Boulangere Potatoes

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…

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.

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).

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).

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

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?!