It’s easy to make French onion soup. Did she say EASY? Yes, it can be easy, with a few simple steps and a slow cooker.
Let’s start with the onions. While most recipes state that onions cooked on the stove caramelize in 15 or even 25 minutes, you’re lucky if they are done in 45 minutes. Since caramelizing onions truly requires more time than many of us have for an average weeknight recipe, this method of “low and slow” caramelizing in the slow cooker over night will not only be a time saver, but will also produce a rich, deep savory flavor perfect for your soup starter. Add all the remaining ingredients to the slow cooker in the morning and go on with your day!
This recipe is for an onion soup without the thick crusted topping. But if that is your preference, see our Gr8 tip below. Delicieux!
Start this the night before you want to serve it because the onions caramelize in the slow cooker overnight!
Toss sliced onions with melted butter, oil and salt and place them in a lightly greased slow cooker.
Fill each bowl 2/3 full of soup.
Sprinkle the bread slices with 2 Tablespoons each of the Parmesan and Gruyère cheeses.
For a thick and beautifully melted crusted topping, use oven-safe crocks and thicker pieces of bread. Top each bowl with sliced (not shredded) Gruyère or Swiss cheese overlapping the slices onto the sides. Broil until the cheese softens and cascades over the side of the crock, about 5 minutes.
To get the very thinnest slices of onions, use a mandolin.