Bring the potatoes with enough cold water to cover to a boil in a small saucepan. Cook, over medium-high heat, until the potatoes are tender, 6 to 8 minutes; drain and pat dry.
Whisk together the eggs, egg whites, coriander, salt, and hot sauce in a large bowl.
Preheat the grill to medium-high.
Heat the oil in a medium (10-inch) ovenproof nonstick pan over medium-high heat. Add the garlic and onion and cook, stirring occasionally, until the onion is translucent, 2 minutes. Add courgette and cook until tender, about 6 minutes more. Add the cooked potatoes and cook, stirring occasionally, until the potatoes begin to brown slightly, about 4 minutes more.
Evenly pour the egg mixture over the vegetable mixture. Cook, over medium heat, tilting the pan and lifting the edges with a rubber spatula to let the uncooked egg flow underneath. Sprinkle with the cheese and the bacon, if using. Broil, 5 to 7 inches from the heat, until the eggs puff and are just set and the cheese is golden brown, about 5 minutes. Remove carefully to a plate, or serve in wedges directly from the pan.