Preheat a grill pan.

Lightly brush both sides of the bread with olive oil.

Grill the bread over high heat, turning once, until lightly charred and crisp, about 30 seconds per side.

Transfer the grilled bread to plates.

Heat 3 tablespoons of olive oil in a large skillet.

Add the oyster mushrooms to the skillet.

Season with salt and pepper and cook over moderately high heat, stirring occasionally, until softened and browned, about 5 minutes.

Add the minced garlic and cook, stirring, until fragrant, about 2 minutes.

Spread the cooked mushrooms on the toasted bread.

Add the Serrano ham to the skillet.

Cook over moderately high heat until warmed through and slightly crisp, about 5 seconds per side.

Place the cooked ham over the mushrooms on the toast.

Crack the eggs into the skillet and fry them over easy.

Top each toast with a fried egg.

Sprinkle with the chopped parsley and serve immediately.