Fish Sauce Caramelized Onions

Patis Caramelized Onions are rich, savory onions cooked with Filipino fish sauce for a deep umami flavor. This easy condiment uses only four simple ingredients and can be made in under an hour, making it a flavorful topping for burgers, hot dogs, sandwiches, fries, pizza, savory pastries, and more.

Traditional caramelized onions are delicious, but they can take a long time to cook. This recipe uses a faster steaming method to soften the onions first, helping you build sweet, golden, deeply savory flavor in about 25 to 40 minutes of cooking time.

The secret ingredient is patis, a Filipino fish sauce that adds saltiness, complexity, and an unmistakable umami finish. Instead of using plain salt, patis seasons the onions while giving them a more layered, savory taste.

For more easy condiments and side dishes, explore our sauce recipes and side dishes, including Toyomansi and Sweet and Sour Sauce.

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Table of Contents

What is Patis?

Patis is Filipino fish sauce. It is commonly used in Filipino cooking as both a seasoning and a dipping sauce. Unlike some other fish sauces, patis is known as a byproduct of the bagoong industry, giving it a distinct place in Filipino cuisine.

In many Filipino kitchens, patis is a go-to ingredient for adding saltiness and savory depth. A small amount can make soups, stews, marinades, sauces, and simple vegetable dishes taste fuller and more balanced.

The flavor of patis can vary depending on the brand. Some versions are saltier, some are more pungent, and others have a stronger umami taste. For this recipe, start with 1 to 2 tablespoons of patis, then adjust to your preference. It is always easier to add more than to fix onions that have become too salty.

Preparing Caramelized Onions with Patis

Caramelized onions are made by slowly cooking onions until their natural sweetness develops and their color deepens. Salt helps draw out moisture from the onions, which allows them to soften and brown more evenly.

In this version, patis replaces the usual salt. It seasons the onions while adding a savory, slightly briny complexity that plain salt cannot provide. As the onions cook down, the patis blends with the butter and natural onion sugars, creating a condiment that is sweet, salty, and deeply umami.

If you enjoy caramelized onions on burgers, hot dogs, or sandwiches, this Filipino-inspired version will feel familiar but more flavorful. The fish sauce does not overpower the onions; instead, it makes them taste brighter, richer, and more savory.

Caramelized Onions Tips + Tricks

Use these tips to make quick caramelized onions with better texture, color, and flavor:

• Steam the onions first.
  • Covering the onions with a lid and steaming them for 5 to 10 minutes helps them soften faster. This shortens the overall cooking time and makes the caramelizing process easier.
• Choose the right pan.
  • Stainless steel and cast iron pans are great for browning because they heat well and encourage caramelized bits to form on the surface.
  • A nonstick pan can also work and may make cleanup easier, but the onions may take longer to caramelize fully.
• Let the onions brown without burning.
  • Once the liquid has evaporated, spread the onions evenly across the pan. Let them sit briefly so they can brown, then stir only as needed to prevent burning.
  • Deglaze with water whenever browned bits begin sticking to the pan. A small splash of water loosens those flavorful bits so they can mix back into the onions and deepen the color.
• Adjust the patis to taste.
  • Because fish sauce varies by brand, begin with less and add more if needed. The finished onions should taste savory and balanced, not overly salty.

Serving and Pairing Suggestions

These Patis Caramelized Onions are a versatile Filipino-inspired condiment that can instantly upgrade simple meals. They are rich enough for comfort food but balanced enough to pair with lighter dishes.

Try them in Filipino Caramelized Onion Tarts, where the savory onions pair beautifully with Eden cheese for a familiar yet creative Filipino flavor combination.

They are also delicious with:

• Burgers
• Loaded fries
• Hot dogs
• BBQ pizza
• Sandwiches and wraps
• Savory pastries

You can also spoon them over grilled meats, add them to rice bowls, or use them as a savory layer in party appetizers.

Equipment

• Large skillet or sauté pan
• Lid
• Knife
• Cutting board
• Wooden spoon or spatula

Ingredients

• 3 large yellow onions
• 3 tbsp unsalted butter
• 2 tbsp patis, Filipino fish sauce, or to taste
• Black pepper, to taste

Recipe

1. Slice the onions into half-moon strips.

2. Place the onions in a pan and pour in enough water to reach about 1/4 inch in depth.

3. Cover the pan with a lid and turn the heat to high. Steam the onions for about 10 minutes, or until they are softened.

4. Add the butter and patis.
5. Lower the heat to medium-high and continue cooking with the lid off. Stir the onions and let the moisture evaporate.

6. Once the liquid has evaporated, spread the onions evenly across the pan. Stir less often so the onions can brown, stirring only to prevent burning, about every 2 minutes. Continue for 20 to 30 minutes.

7. Deglaze the pan with small splashes of water as needed. Continue cooking until the onions are nicely browned. Stop at a light golden brown color, or keep cooking longer for a deeper caramelized shade.

Final Thoughts

These Patis Caramelized Onions are an easy way to bring Filipino flavor into everyday meals. They are buttery, savory, sweet, and packed with umami from Filipino fish sauce. With only four ingredients and a quicker cooking method, this condiment is simple enough for weeknights but flavorful enough for entertaining.

Use them anywhere you would normally add caramelized onions, especially when you want extra depth and a subtle Filipino twist. They are excellent on burgers, hot dogs, sandwiches, loaded fries, and savory pastries.

If you love cooking with patis, try more Filipino recipes like Pancit Bihon and Comforting One-Pot Sinigang.

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References & Further Reading

Fish sauce background, patis usage, and caramelized onion cooking techniques were referenced for context and recipe development.