Onion Aioli

Onion aioli is what happens when caramelized onions crash the garlic-mayo party — and everyone is glad they came. Sweet, deeply savory and creamy, it upgrades burgers, sandwiches, roasted vegetables and fries without asking anything difficult of the cook.

The only real work is the caramelizing, and it refuses to be rushed: 15 to 20 patient minutes turn sharp onion into golden sweetness. Everything after that is stirring.

A batch keeps a week in the fridge, which is exactly long enough to discover how many things it improves. (Spoiler: most things.)

Onion Aioli Recipe

Prep time: 10 minutes (plus 1 hour chilling) · Cook time: 20 minutes · Total: about 1½ hours · Servings: 1 cup (about 8 servings) · Calories: ~113 per serving

Ingredients

• 1 medium onion, finely chopped
• 3 garlic cloves, minced
• 1 cup mayonnaise
• 2 tablespoons olive oil
• 1 tablespoon lemon juice
• Salt and freshly ground black pepper
• 1 teaspoon Dijon mustard or honey (optional)

Instructions

1. Caramelize the onion in the olive oil with a pinch of salt over medium heat, stirring occasionally, 15 to 20 minutes, until golden. Cool to room temperature.
2. Mix the mayonnaise, garlic, lemon juice, and the Dijon or honey if using.
3. Stir in the cooled onions until evenly distributed.
4. Season with salt and pepper, adjusting lemon or oil to taste.
5. Refrigerate at least an hour to let the flavors marry, and stir before serving.

Recipe Notes

• Yellow or sweet onions caramelize best; red brings a bolder edge.
• Low and slow is the caramelizing law — burnt onion forgives nothing.
• Sauté the garlic briefly with the onions for a mellower aioli, or add a pinch of garlic powder to go louder.
• Keeps a week refrigerated in a sealed jar.