Whisk the mayonnaise, pepper brine, mustard, rosemary and 1 tablespoon water in a small bowl. Season with salt and pepper. Spread evenly on the cut sides of the rolls. Heat 1 1/2 inches olive oil in a pot over medium-high heat until a deep-fry thermometer registers 350 degrees F. Line a baking sheet with paper towels. Whisk the flour, 1 teaspoon salt and 1/2 teaspoon pepper in a large bowl. Whisk the eggs and 2 tablespoons water in another bowl. Toss the onions in the flour, then fry in the hot oil until crisp, about 1 minute. Transfer to the prepared baking sheet to drain. Toss the mushrooms in the flour, dip in the egg mixture and toss again in the flour; fry in batches until golden, about 2 minutes. Drain on the baking sheet and season with salt and pepper. Fill the rolls with the ham, Peppadew peppers, and fried onions and mushrooms.
Photograph by Antonis Achilleos
Courtesy of Food Network Magazine