Why It Works
- The pressure cooker cooks at a higher temperature to produce onions that are caramelized in a fraction of the time of a traditional recipe.
- Baking soda speeds up the Maillard reaction.
Editor's Note: Due to reader complaints and further testing, we no longer recommend this method for caramelizing onions. For a quick method that yields better texture and flavor, try our 15-minute caramelized onions. For best results, however, we strongly recommend caramelizing onions the traditional way, low and slow.
- 6 tablespoons unsalted butter (3 ounces; about 90g)
- 3 pounds yellow or mixed onions, sliced 1/8 inch thick (1.4kg; about 4 to 5 large onions) (see note)
- 1/2 teaspoon (2g) baking soda
- Kosher salt and freshly ground black pepper
Melt butter in an electric or stovetop pressure cooker over medium heat. Add onions and baking soda and stir to combine. Season with salt and pepper. Cook, stirring, until onions slightly soften and start to release liquid, about 3 minutes. Seal pressure cooker and heat to high pressure (12.5 to 15 psi). Cook at high pressure for 20 minutes. Release pressure by allowing steam to vent, then remove lid.
Continue cooking with lid off, stirring constantly, until liquid inside has completely reduced and the onions are deep brown and sticky, about 5 minutes. Caramelized onions can be stored in a sealed container in the refrigerator for up to 10 days or frozen for several months.
Yellow onions are your best all-purpose bet for caramelized onions, but a mix of yellow, sweet (e.g., Vidalia), and red onions, as well as shallots, produces an even more complex flavor.