Caramelized Onion Toast

Name: Caramelized Onion Toast
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Yield: 4 servings
Cuisine: American
Ingredients: 2 lb yellow onions, thinly sliced; 2 tbsp unsalted butter; 2 tbsp olive oil; 2 cloves garlic, minced; 1 tsp fresh thyme; 2 tsp balsamic vinegar; 8 slices sourdough bread, sliced; 1 cup Gruyere cheese, shredded; 1/2 tsp salt; 1/4 tsp black pepper

Deeply caramelized onions with garlic and thyme piled onto toasted sourdough and finished with melted cheese; the slow-cooked toast that took over Instagram Reels in July 2026.

50 minMediumServes 4480 cal/serving

AmericanAppetizerStovetop and OvenVegetarianLow CarbLow-SodiumPork-FreeCorn-Free

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Ingredients

2 lb yellow onions, thinly sliced
2 tbsp unsalted butter
2 tbsp olive oil
2 cloves garlic, minced
1 tsp fresh thyme
2 tsp balsamic vinegar
8 slices sourdough bread, sliced
1 cup Gruyere cheese, shredded
1/2 tsp salt
1/4 tsp black pepper

Instructions

1

Heat the 2 tbsp unsalted butter and 2 tbsp olive oil in a large skillet over medium-low heat.
2

Add the 2 lb thinly sliced yellow onions and a pinch of 1/2 tsp salt. Cook, stirring occasionally, for 30 to 35 minutes until deeply golden brown and jammy, lowering the heat if they start to catch.
3

Stir in the 2 cloves minced garlic and 1 tsp fresh thyme and cook for 1 minute until fragrant.
4

Remove from the heat and stir in the 2 tsp balsamic vinegar. Season with 1/4 tsp black pepper to taste.
5

Preheat the broiler. Arrange the 8 slices sliced sourdough bread on a baking sheet and toast lightly under the broiler, about 1 minute per side.
6

Top each toast with the caramelized onions and a layer of 1 cup shredded Gruyere cheese.
7

Broil for 2 to 3 minutes until the cheese is melted and bubbling. Serve warm.

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Questions

How long does Caramelized Onion Toast take?

As written, 50 minutes: 10 of prep and 40 of cooking. The longest single stretch is step 2 (35 minutes): "Cook, stirring occasionally, for 30 to 35 minutes until deeply golden brown and jammy, lowering the heat if they start to catch."

What can I use instead of Gruyere in Caramelized Onion Toast?

The entry for Caramelized Onion Toast calls for 1 cup Gruyere cheese, shredded. In its place: Emmental, Jarlsberg or a good Swiss cheese melts the same way. Comte is the closest in flavor.

Can I make Caramelized Onion Toast dairy-free?

Yes. The dairy in Caramelized Onion Toast is 2 tbsp unsalted butter, 1 cup Gruyere cheese, shredded. Swap the butter for olive oil where it melts, or a plant-based block butter where it is creamed; the cheese for a plant-based melting cheese (expect a milder flavor). The richness shifts slightly, but the method does not change.

Can I make Caramelized Onion Toast gluten-free?

Yes. The gluten in Caramelized Onion Toast is 8 slices sourdough bread, sliced. Swap the bread or crumbs for a gluten-free loaf or gluten-free panko. Everything else proceeds as written.

How do I store and reheat Caramelized Onion Toast?

Refrigerate what is left of Caramelized Onion Toast within two hours and eat it within three days. Reheat covered in a 300 F oven until warmed through.

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