Roast Pork Sandwiches with Garlic Mayo Ingredients 1 head garlic Coarse salt Extra-virgin olive oil 1 red onion, halved lengthwise 2 teaspoons Dijon mustard 1/2 cup mayonnaise 4 submarine rolls (10 to 12 inches long), cut in half horizontally 20 to 24 thin slices roast pork Roasted fennel, chiles, and pitted olives (optional) 16 thin