Name: Caramelized Onion Jam
Total time: 2 h 50 min
Ingredients: 3 tablespoons extra-virgin olive oil; 1¼ pounds onions (2 large), halved and sliced thin through root end; 1 bay leaf; ½ teaspoon minced fresh rosemary; ½ teaspoon salt; ¼ teaspoon pepper; 2 garlic cloves , peeled and smashed; ¼ cup balsamic vinegar; ¼ cup water; 2 tablespoons sugar

Why This Recipe Works

Caramelized onion jam is quite versatile, pairing well with a wedge of cheese, as part of a sandwich, or spread on pizza. After an initial round of testing, we realized that the process of caramelization can't begin until the onions start to release their juices. This release of moisture indicates that the cell walls are breaking down, turning complex starches into simple sugars. These sugars caramelize, darken, and add complex flavors to our savory onion jam. We started out by cooking onions, bay leaves, rosemary, salt, and pepper in a Dutch oven until golden brown, which took far too long and left us with a stringy, pasty, dried-out texture. We found that covering the onions for the first 10 minutes of cooking allowed them to release some of their natural liquids without breaking down or burning too quickly. Once the onions caramelized, we stirred in balsamic vinegar, water, and sugar. After the mixture reduced for a short time, it was on its way to a jammy consistency. Minced fresh rosemary and garlic provided earthy, aromatic notes. Pulsing the onion mixture in a food processor gave us the perfect, spreadable texture. Because the shelf life of this jam is so short, the yield is just one jar.

Before You Begin

This jam cannot be processed for long-term storage.

Instructions

Heat oil in Dutch oven over medium-high heat until shimmering. Stir in onions, bay leaf, rosemary, salt, and pepper. Cover and cook, stirring occasionally, until onions have softened and released their liquid, about 10 minutes.

Stir in garlic. Reduce heat to medium-low and cook uncovered, scraping up browned bits, until onions are golden brown, about 15 minutes.

Stir in vinegar, water, and sugar, scraping up any browned bits. Increase heat to medium-high and simmer until mixture is thickened and rubber spatula or wooden spoon leaves distinct trail when dragged across bottom of pot, about 2 minutes.

Discard bay leaf. Transfer onion mixture to food processor and pulse to jam-like consistency, about 5 pulses; let cool slightly.

Using funnel and spoon, portion jam into one 1-cup jar. Let cool to room temperature and serve. (Jam can be refrigerated for up to 4 days; it must be discarded after 4 days.)