Slow Cooker French Onion Soup Recipe (2024)

FAQs

Will raw onion cook in a slow cooker? ›

Just slice up a bunch of onions. (You can use white, yellow, or red onions, or a combination of any of those.) Toss them with some melted butter. Then let them cook on low for about 12 hours total until they reach that perfectly caramelized, deep golden brown, sweet and savory perfection.

A few sprigs of thyme and a bay leaf elevate the soup even more, but I take it a step further, adding a splash of fish sauce for complexity and depth—don't worry, it won't taste fishy—and a hit of cider vinegar to balance some of that oniony sweetness.

You can cook the onions before if you wish, but we found it doesn't really matter if you put them in raw (one less step!) For a slow cooker recipe, there is no need to brown the meat beforehand either. Yes it gives it colour, but it's not essential.

Slow cookers can transform a few simple ingredients into the most delicious soups by simmering them for hours. This low and slow cooking allows the flavors to mingle, creating rich, flavorful soups perfect for chilly days, nights, or any day you want to enjoy a bowl full of goodness.

If you cook red onion with alkaline foods, such as nuts, lentils, and some vegetables, those anthocyanins revert to their blue hue. The same is true of red cabbage. To maintain the red hue, add a little acid, such as a splash of vinegar or a squeeze of lemon juice.

The caramelized onions for this soup cook more quickly due to a pinch of baking soda but still have that deep, slow-cooked flavor.

Onion soup, at its very essence, is nothing more than onions and water boiled together. Period, done, finished, everything added from that point on is pure opinion. Caramelizing the onions brings out sugars, and makes a more luxurious silky and sweet soup, adding flour gently thickens and provides body.

It might be because of the stock or that you used onions that has sour flavor such as white onions.

The difference between "High" and "Low" on slow cookers seems to differ with every brand and model. One thing that is consistent, though, is that food takes seven to eight hours to reach a simmer point (around 210°) on low; versus three to four hours on high.

Can you overcook onions in slow cooker? ›

How Long It Takes to Caramelize Onions in a Slow Cooker. It's almost impossible to overcook these onions, but I've found that 10 hours makes soft, lightly browned onions that still have a bit of bite.

You need to cook them longer, higher temp before simmering or slow cook for alot longer. I sauté the very finely sliced onions on a very low heat for at least 20mins before anything else goes in the pan.

Stick to the cook time indicated on your recipe

Most slow cooker meals take 8-12 hours on low or 4-6 hours on high, but there are also recipes for slow-cooked meat that take up to 24 hours. If you want to avoid overcooking your dish, follow the given guidelines as closely as possible.

"When a slow cooker is too full, it may not heat the food evenly," explains Leal. As a result, some parts of the dish may overcook, while others remain undercooked. "This can also increase the risk of foodborne illness, because the food might not reach a safe temperature throughout," she says.

Use fresh, good quality ingredients like vegetables and herbs. Add a little bit of vinegar or lemon juice to your soup to make it taste better. Use a high-quality broth or stock as a base for your soup. Roast or caramelize your vegetables before adding them to your soup to bring out their natural sweetness.

You really want to give onions at least 8 hours to caramelize properly in a slow cooker. That low and slow cooking process is all about building flavor. If you can, let them go longer! Cook them for up to 12 hours for the richest flavor possible.

Tender vegetables

Vegetables such as peas, asparagus and peppers can become a flavorless, mushy mess in a slow cooker. Stick to heartier root vegetables like potatoes, onions, leeks and yams, or wait to add the tender vegetables until the last 30 minutes or so of cooking time.

Add chopped or sliced onions and cook for 5 to 7 minutes or until tender, stirring frequently with a wooden spoon or heatproof spatula. That's the time it takes to sauté onions so the harsh onion flavor is removed, and they barely start to sweeten.