How to Make Caramelized Onions for Maximum Flavor

Once you master caramelized onions, there is no going back. It’s a skill that you’ll reach for again and again. Consider this your ultimate guide to getting perfectly jammy, rich, deep, and sweet caramelized onions every single time.

It’s incredible how something so pungent, when raw, can turn so deliciously sweet and decadent. It’s thanks to the Maillard reaction, where the natural sugars break down when heated slowly.

I’ll never forget the first time I tried to make caramelized onions. In my late teens, my sister and I thought they’d be the perfect topping for a homemade goat cheese pizza. In the true spirit of pizza night, I wanted something quick and easy, so I cranked the heat up, thinking it would speed up the caramelization process. Spoiler alert: it didn’t. I’ve learned a lot since then!

After those onions (which burnt before they could caramelize), I made it my mission to perfect the art of caramelizing onions, testing every tip and trick I could find. You name it, I’ve tried it. In the end, the secret to the best caramelized onions always comes down to one thing: time!

What kind of onions are best for caramelized onions

Technically, you can use any onion for this recipe (you could even use shallots!) However, you’ll get the best results with onions that are higher in sugar, such as yellow or red onions. I usually opt for yellow onions, as I find red onions have a slightly bitter finish.

Does baking soda speed up caramelizing onions?

Technically, the baking soda raises the pH of the onions, which, in theory, speeds up browning. But there is a catch – it also breaks down the structure of the onion, turning your caramelized onion recipe into mush. It also changes the taste, leaving an odd bitterness, even with small amounts. Leave the baking soda in the cupboard and give the onions a bit more time instead. If you want to speed things up a little bit, you can cover the pan with a lid in step 3 to shave off a few minutes.

Storing and reheating

Store: Once cooled, transfer the caramelized onions to a container and refrigerate for up to 7 days.

Freeze: Sometimes, I batch-cook the onions since it’s such a slow process. I’ll make double the recipe and freeze some for when we have a spontaneous pizza night. Store them in a freezer-proof container for up to two months.

Reheat: Gently reheat your caramelized onions in a skillet, adding olive oil if needed.

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How to Make Caramelized Onions for Maximum Flavor

Prep: 10 minutes mins

Cook: 50 minutes mins

Total: 1 hour hr

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Recipe video below. This step-by-step process will give you beautifully jammy caramelized onions.

4

Ingredients

• ▢ 3 large onions (any kind!)
• ▢ 2 tablespoons butter
• ▢ ¼ teaspoon salt
• ▢ Water (for deglazing the pan)

Instructions 

• Start by vertically slicing your onions. Cut both ends off the onion, rest it on one of the cut ends, cut it in half, and then peel the onion. Lay the onion halves on your cutting board and then make slices going in the same direction as the grain – NOT into half moons. Slice until you reach the center of the onion half, then turn it down so that it's not so high and easier to cut.
  3 large onions
  
• Turn your largest element on to medium-high. Melt the butter in your largest cast-iron or stainless-steel pan (see notes), then immediately add the onions without waiting for the pan to fully heat.
  2 tablespoons butter
  
• Cook the onions, stirring frequently, for 8-10 minutes until they are soft.
  
• Lower the heat to medium-low, add the salt, and continue to cook the onions, stirring frequently, for another 20 minutes. At this point, they will look golden blond and be perfect for French onion soup.
  ¼ teaspoon salt
  
• For slightly darker onions (say for a patty melt or pizza topping), continue cooking, stirring frequently, until they are golden brown, about 15-20 minutes more.

  As you cook the onions, scrape the bottom of the pan to loosen the fond (the dark bits) and mix it into the onions. (Fond is concentrated bits of flavor, so they'll add lots of depth.) If it gets too stuck, add a splash of water to deglaze the pan and prevent it from burning. You can do this as many times as needed. If the onions are browning too quickly, lower the heat even more.
  Water
  
• For dark caramelized onions (perfect for topping a burger or serving with pierogies), continue cooking until they are dark brown and ever so slightly crisp at the edges. Don't walk away from the pan at this step, as this is where you're most likely to burn them. Lower the heat and add water to the pan as needed.
  

Video

Notes

Cutting the onion: This is one recipe where cutting the onion in a specific way is essential. You want to use a vertical slice, and I’ve outlined how to do so in the directions. Make sure to cut them this way for the best caramelized onions!

Type of pan: Onions caramelize best in cast iron or stainless steel pans; avoid non-stick or enameled cast iron. Choose your largest pan for this job so that as many onions as possible have contact with it. 

Butter: I prefer butter because it helps prevent the onions from sticking to the pan and adds wonderful flavor. But you can use olive oil if you prefer.

How long to cook the onions: That depends on how caramelized you want them! You can stop cooking them after Step 4, Step 5, or Step 6 – it’s up to you!

Quick caramelized onions: For the best caramelized onions, there are no shortcuts. But here are two things you can do if you’re short on time. 1: Cover the pan in step three. This will shave a few minutes off the cook time. 2. Keep the heat higher. This increases the chances of them burning, so watch them diligently and keep a glass of water on hand. 

Deglazing your caramelized onions: In the recipe, I suggest deglazing the pan with water. This dissolves the fond, boosting the flavor while also preventing burning. Depending on what you’re making, switching up your deglazing liquid can add extra depth and flavor—you could also use broth, white or red wine, sherry, balsamic vinegar, or bourbon.

Nutrition

Serving: 1 = ¼ of the recipe, Calories: 95kcal (5%), Carbohydrates: 11g (4%), Protein: 1g (2%), Fat: 6g (9%), Saturated Fat: 4g (25%), Polyunsaturated Fat: 0.2g, Monounsaturated Fat: 1g, Trans Fat: 0.2g, Cholesterol: 15mg (5%), Sodium: 195mg (8%), Potassium: 166mg (5%), Fiber: 2g (8%), Sugar: 5g (6%), Vitamin A: 177IU (4%), Vitamin C: 8mg (10%), Calcium: 28mg (3%), Iron: 0.2mg (1%)

© Author Kristen Stevens

We have thoroughly tested this recipe for accuracy. However, individual results may vary. See our full recipe disclosure here.

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