Heat the olive oil in a skillet over a medium flame, and sauté the onions until translucent.

Add the mushrooms and garlic and stir to coat in oil. Season with salt, pepper, and cayenne. Sauté until everything has caramelized, about 12 to 15 minutes.

Place the egg slices on a serving plate or over bread. Spoon the mushroom mixture over the eggs and garnish with cilantro. Serve warm or cold.