8 slices prosciutto di Parma
4 slices (1/4- to 1/2-inch-thick) red onion
Olive oil, for drizzling
Salt and pepper
4 thick slices ripe beefsteak tomato
4 slices (1/4- to 1/2-inch-thick) white peasant-style bread
2 large cloves garlic, halved EVOO, for drizzling
A pat of butter, for the eggs
4 large eggs
About 1 to 1 1/2 cups arugula
Calabrian chili paste or hot sauce of your choice, for serving
Preheat the oven to 375°. On a parchment paper–lined baking sheet, arrange the prosciutto. Bake until crisp, about 10 minutes. Transfer on the paper to a wire rack; let cool.
Heat a cast-iron skillet over medium-high. Drizzle the onion slices with olive oil; season with salt and pepper. Cook until browned, 2 to 3 minutes per side. Transfer to a plate. Season the tomato slices; cook until browned in spots, about 1 minute per side. Transfer to the plate with the onions. Scrape or wipe out the skillet; heat over medium-low.
Working over an open flame or under the broiler, char the bread. Rub the bread with the cut sides of the garlic cloves. Drizzle with EVOO; season with salt.
Add the pat of butter to the cast-iron skillet. Add the eggs and cook until over easy to hardfried or to your liking; season.
Top each slice of charred bread with a tomato slice, a few arugula leaves, an onion slice, crispy prosciutto, and an egg. Drizzle with Calabrian chili paste.