Photo of Grilled Gruyère & Caramelized Onion Sandwiches by WW

Grilled Gruyère & Caramelized Onion Sandwiches

Total Time
22 min
6 min
16 min
Gruyère pairs so well with onions (it’s the cheese typically served with French onion soup). It’s an equally winning combo in this upscale grilled cheese. Dijon mustard, which is made from brown mustard seeds and white wine, adds a sharp flavor with a hint of spice to this melt-in-your-mouth sandwich. Dijon mustard is an excellent ingredient to use in recipes because you just need a small amount, adding big flavor without too many calories. This sandwich is also tasty made with Swiss, Fontina or Cheddar cheeses. Serve it with Brussels sprouts or fruit.


Cooking spray

3 spray(s)

Uncooked onion(s)

½ medium, sweet-variety, thinly sliced (about 1 cup)

Reduced-calorie wheat bread

4 slice(s)

Dijon Mustard

2 tsp

Gruyère cheese

2 oz, shredded (about 1/2 cup)


  1. Coat a large nonstick skillet with cooking spray; heat over medium heat. Add onions; reduce heat to medium-low and cook, stirring often, until tender and golden brown, about 8 to 10 minutes. Remove onions to a plate.
  2. Lay 2 slices of bread on a work surface; spread each with 1 teaspoon mustard. Top each with half of the cheese and onions; cover each with a second piece of bread.
  3. Wipe skillet clean; heat over medium-low heat. Coat sandwiches with cooking spray. Cook until bottoms are browned, about 2 minutes. Carefully flip sandwiches over and cook until browned on other side and cheese is melted, about 2 minutes more. Slice each sandwich in half and serve.
  4. Yields 1 sandwich per serving.