Preparation

Make the aïoli

• Peel, mince, and mash the garlic to a paste with a pinch of salt. In a food processor, pulse the egg yolk, vinegar, mustard, garlic paste, and 1/2 tsp. salt until combined. With the machine running, drizzle in the olive oil until the mixture is emulsified. Add the herbs and pulse once or twice to combine. Transfer to a small bowl and season to taste with salt.

Make the burgers

• Prepare a medium (350°F) gas or charcoal grill fire.
• In a medium bowl, combine the ground beef, basil, marjoram, rosemary, 1 tsp. salt, and a few grinds of pepper. Form into four 1/2-inch-thick patties. Press the center of each patty with 3 fingers to make an indentation.
• Grill the burgers, covered, flipping once, until cooked to your liking, about 6 minutes for medium rare (125°F).
• Transfer the burgers to a plate and keep warm.
• Toast the buns cut side down on the grill. Serve the burgers on the buns, topped with the aïoli, lettuce, and tomato, if using.

Make Ahead Tips

The aïoli will keep, covered and refrigerated, for up to 5 days.

Note: The aïoli contains a raw egg yolk; if that’s a concern, use pasteurized eggs.