
Slow Cooker French Onion Chicken - Boneless chicken breasts are topped with gooey Swiss cheese on a bed of thinly sliced onions in this crock-pot French onion chicken recipe.
The crock-pot does all the work of coaxing the onions into a caramelized state, a task that would take at least 30 minutes on the stove top while you babysit them the entire time, maybe longer.
If you never had a caramelized onion before then you are sincerely missing out on something special and you absolutely have to make this.
Thinly-sliced yellow onions are mixed with melted butter, Dijon, Worcestershire, a touch of sugar, salt and pepper plus a little flour to help thicken the flavorful juices that come out of them as they cook so you can spoon it over the chicken.
Slow-cooking the chicken causes it to be so tender you can slice through it with a fork. Just like butter.
Get this in your crock-pot in the morning and sit down later to one of the easiest, most comforting and delicious meals ever.
FREQUENTLY ASKED QUESTIONS :
Can I use chicken thighs instead of breasts?
Yes, boneless skinless thighs work great and tend to stay juicy even after longer cooking times. Just trim excess fat if needed.
Can I use a different cheese?
Absolutely. Provolone, gruyere, or mozzarella all melt beautifully and pair well with the onion flavor. Swiss gives that classic French onion vibe, but you can definitely switch it up.
Do I need to pre-cook the onions?
Nope! The slow cooker does the work. The trick is slicing them evenly and letting them cook low and slow so they caramelize naturally.
What’s the best way to serve this?
We love it over mashed potatoes, rice, or even thick slices of toasted baguette to soak up the sauce. Add a green veggie or salad on the side and dinner’s done!
Can I make this ahead of time?
Yes! The leftovers are amazing. Store in the fridge for up to 3 days and reheat gently in the microwave or on the stovetop.
📖 Recipe

Slow Cooker French Onion Chicken
Ingredients
- 6 cups sliced about ⅓-inch wide yellow onions (about 1 pound)
- 2 tablespoons melted butter
- 1 tablespoon Worcestershire sauce
- 1 rounded teaspoon Dijon mustard
- 1 tablespoon all-purpose flour
- 1 teaspoon sugar
- 1 teaspoon fresh thyme leaves or ¼ teaspoon dried
- sea or kosher salt and fresh black pepper
- 3 - 4 boneless chicken breasts
- 1 + ⅓ cups shredded Swiss cheese or 3 - 4 thick slices
Instructions
- Spray a 4 or 5 quart crock-pot with non-stick spray. Add the onions.
- In a small bowl whisk together the butter, Worcestershire, Dijon, flour, sugar, thyme and ½ teaspoon salt plus ¼ teaspoon black pepper.
- Pour it over the onions and toss to coat.
- Place the chicken breasts on top of the onions. Season well with salt and pepper.
- Cook on low 5 - 7 hours or high 3 - 4.
- Top the chicken with the cheese and put the lid on to melt.
- To serve place the chicken breasts on a platter and top with the onions. Ladle the juice over them.
Nutrition
This slow cooker French onion chicken is one of those set-it-and-forget-it meals that delivers big flavor with hardly any work. It’s rich, cozy, and feels kind of fancy—but it’s really just everyday ingredients layered with love.
Perfect for busy weeknights, lazy Sundays, or even entertaining. And if you serve it with a glass of red wine and a crusty loaf of bread? You’re living the dream.
Let me know if you give it a try—I’d love to hear how it turned out!
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