Instant Pot Caramelized Onion Vinaigrette

Name: Instant Pot Caramelized Onion Vinaigrette
Prep time: 10 min
Cook time: 25 min
Total time: 35 min
Yield: 8 servings
Cuisine: French
Ingredients: 2 medium (400 g) yellow onions, large, thinly sliced into half-moons; 2 whole (80 g) shallots, medium, thinly sliced; 2 tablespoons (30 ml) extra-virgin olive oil; 3 tablespoons (45 ml) balsamic vinegar; 1 tablespoon (15 ml) red wine vinegar; 1 teaspoon (5 ml) Dijon mustard; 1 small (4 g) garlic clove, minced, minced; ½ teaspoon (2½ ml) honey; to taste fine sea salt; to taste freshly ground black pepper; 2 sprigs fresh thyme sprigs (optional)

From the MyKitchenBank Kitchen

A silky French-inspired vinaigrette built on deeply caramelized onions and shallots cooked under pressure, then emulsified with balsamic vinegar, Dijon mustard, and olive oil. The Instant Pot develops rich, sweet onion flavor in 25 minutes instead of the hour-long stovetop method. Perfect drizzled over bitter greens, roasted vegetables, or grilled steak.

Prep: 10 min
Cook: 25 min
Wait: 5 min
Total: 40 min
Makes: About 1 cup (240 ml)

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Steps

Before you start

Have a 6-quart Instant Pot ready with the sauté lid or regular lid at hand
Slice onions and shallots evenly so they cook at the same rate
Measure all vinegar and seasonings before starting so they're handy after pressure cooking
Gather a small bowl and whisk for the final emulsification

1
Sauté the alliums
- Set your Instant Pot to the sauté function on medium-high heat.
- Once the inner pot is hot (about 1 minute), add the 2 tablespoons (30 ml) of olive oil.
- Immediately add the sliced onions and shallots, stirring to coat in oil.
- Cook for 3–4 minutes, stirring frequently, until they begin to soften and the bottoms just start to caramelize (look for light golden edges).
- This head start ensures deeper flavor development under pressure.
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Ready when: Onions and shallots are softened and light golden at the edges
Tip: Don't skip this sauté step—the initial caramelization develops flavor that pressure cooking will deepen.
2
Pressure cook the onions
- Add 1/4 cup (60 ml) of water and the thyme sprigs (if using).
- Stir to dislodge any browned bits from the bottom.
- Cancel the sauté function and secure the lid.
- Set to high pressure for 12 minutes.
- The water helps create steam while the onions continue to soften and release their sweetness under pressure.
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Ready when: Instant Pot beeps after pressure cooking is complete
Tip: Use a timer so you don't accidentally release pressure early.
3
Natural release and drain
- When the timer finishes, allow the Instant Pot to naturally release pressure for 5 minutes, then carefully move the steam release valve to venting position to release any remaining pressure.
- Open the lid away from your face.
- You may see some liquid—that's fine.
- Using a fine-mesh strainer or slotted spoon, transfer the cooked onion mixture to a small bowl, allowing excess liquid to drain back into the pot.
- Discard the thyme sprigs if used.
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Ready when: All pressure is released and onions are very soft and dark golden
Tip: Drain excess liquid so the vinaigrette isn't watery; you want the concentrated onion flavor.
4
Build the emulsion
- In a small bowl, whisk together the balsamic vinegar (3 tablespoons / 45 ml), red wine vinegar (1 tablespoon / 15 ml), Dijon mustard (1 teaspoon / 5 ml), minced garlic (1 clove / 4 g), honey (1/2 teaspoon / 2.5 ml), and a pinch each of sea salt and black pepper.
- Let it sit for 1 minute so the flavors meld.
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Ready when: Vinegar mixture is combined and fragrant
Tip: Whisking the vinegar base before adding onions helps the mustard emulsify evenly.
5
Combine and emulsify
- Add the drained caramelized onions and shallots to the vinegar mixture.
- Whisk vigorously for 1–2 minutes.
- The onions' natural gelatin will help create a silky, slightly thick emulsion.
- Taste and adjust seasoning with a pinch more salt or pepper as needed.
- If you want a thinner consistency, whisk in 1–2 teaspoons (5–10 ml) more vinegar.
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Ready when: Mixture is silky, slightly thick, and well combined
Tip: The vinaigrette will thicken slightly as it cools; don't over-thin it at this stage.

Good to know

Tips

This vinaigrette coats bitter greens beautifully—try it on frisée, endive, or radicchio.
Serve it warm or at room temperature over roasted root vegetables, grilled steak, or creamy burrata.
The natural gelatin from the pressure-cooked onions creates body without added oil, making it less heavy than traditional vinaigrettes.
If you don't have an Instant Pot, slowly caramelize the onions and shallots in a heavy skillet over medium-low heat for 45 minutes to 1 hour, stirring often, then proceed with the vinegar base.

Make ahead

Store in the refrigerator for up to 5 days. Make it a day or two ahead for deeper flavor development. Bring to room temperature and whisk well before serving, as the emulsion may separate slightly during storage.

Storage & reheating

Room temperature: up to 2 hours. Refrigerator: up to 5 days (it will thicken and may separate slightly; whisk well before use). Freezer: not recommended due to the emulsified texture. Reheat gently on the stovetop over low heat if desired, whisking constantly.

Substitutions

balsamic vinegar → sherry vinegar (3 tablespoons / 45 ml). Gives a slightly lighter, more delicate sweetness. Use the same amount.
red wine vinegar → white wine vinegar (1 tablespoon / 15 ml). Milder acidity; the dressing will be slightly less tangy but still balanced.
Dijon mustard → whole-grain mustard (1 teaspoon / 5 ml). Adds texture and a slightly more rustic, grainy finish.
honey → a pinch of sugar (1/4 teaspoon). Use less because sugar is sweeter than honey; adjust to taste.