Make a Lazy Version of This Classic French Onion Sauce

Onions are popular here at Skillet. Raw or cooked, whole or chopped, they can bring balance and distinctly savoury flavours to a dish. One of my favourite ways to sneak in the complexity of this delightful allium is in a sauce. This one is cheap, creamy (yet cream-less), and it makes any dish feel a tad bougie without trying too hard. Boost your savoury dishes with a lazy soubise sauce.

A classic soubise sauce is the oniony derivative of the mother sauce, béchamel, and béchamel is just milk thickened with a white roux. It’s understandable that we go with the French phrasing; “white roux onion sauce” doesn’t quite roll off the tongue. Modern iterations of soubise sauce use cream instead of béchamel, but I prefer the heft of the roux and my boyfriend is sensitive to heavy cream. (He can handle some dairy, but heavy cream is a hard no for him.) Classically, the roux is transformed into a béchamel separately and reserved. The onions are sautéed in butter and blended into a purée. Finally, the two are combined to make a soubise sauce. Mine is more casual, with fewer dishes to clean.

This lazy soubise is all done in one session, and built in one pot with optional puréeing. Chop the onion into small pieces. I would call it a messy, fine dice, but you could take it down to a mince. The pieces shouldn’t be much larger than a quarter-inch, unless you plan on puréeing it later. Melt the butter in a medium pot over medium-low heat and add the diced onion with a big pinch or two of salt. Use a wooden spoon to move everything around and coat the onion in butter. Meanwhile, warm up the milk in the microwave for about a minute, until the liquid is gently steaming. I like to use a Pyrex measuring cup so it’s easy to pour later. Occasionally stir the onions so they sweat evenly. They should become translucent, but not caramelised. Knock down the heat if the onion starts picking up colour before cooking through. That’s not to say you should worry if the onions do get a bit brown. The flavour will be great regardless, but soubise sauce is usually a blonde sauce.

Once the onions are cooked through and softened, toss in the flour and stir. The mixture will become clumpy as the flour soaks up the fat. Stir for about three minutes. The aroma and colour will change slightly to a nutty, toasty scent, and the colour will become golden. These are subtle changes, so if you can’t identify them at first, it’s ok. The goal is to cook off the raw flour flavour, and that only takes a couple minutes.

Switch to a whisk and slowly pour the heated milk into the pot. I do this in about four installments, but it takes some coordination and usually an apron to protect from splashing. Drizzle and whisk until smooth each time, but keep in mind the onions will remain chunky. (Which is a great way to hide lumps if you have any.) Take it off the heat. If you’d like, you can use an immersion blender to quickly purée the sauce until completely smooth, but I leave the onion bits as-is.

Whisk in a dash of black pepper and you’re ready to dress your dish. The sauce is rich, luscious, savoury, and a touch salty, perfect for dressing nearly any roasted meats or vegetables. Soubise makes a great condiment as well. Add a schmear to sandwiches, eggs, eggplant rollatini, or substitute it in for tomato sauce on your next pizza. Explore new flavours by adding different spices that complement the flavours in the rest of your dish. Try adding cumin, mustard powder, chipotle chilli, garlic, soy sauce, or mix in chopped herbs. You can make this sauce with non-dairy milks, it will still be thick and luxurious, but keep in mind the flavour will be slightly different depending on the milk. Use this sauce immediately, or make it in advance and keep it in the fridge, well-covered, for up to five days. To reheat, simply microwave it, or rewarm it in a pot and stir until smooth.

Lazy Soubise Sauce

Ingredients:

• 1 ½ tablespoons butter
• ½ small onion, finely diced or minced
• ½ teaspoon salt
• 2 tablespoons flour
• 1 cup milk, hot
• Pinch of black pepper

In a medium pot over medium-low heat, melt the butter. Stir in the chopped onions and salt with a wooden spoon. Sweat the onions until they become translucent, but not brown, about 5-8 minutes. Add the flour and stir frequently for about 3 minutes. The mixture will smell toasty. Switch to a whisk and slowly drizzle in the hot milk. Whisk until smooth. Add a pinch of black pepper and use immediately.