Lay the bacon into a large, cold non-stick frying pan on a medium heat and cook for 2 to 4 minutes on each side, or until crisp.
Toast the bread then tear into a food processor. Add the bacon and blitz into a bacon-y crumb.
Halve the leek lengthwise, clean and finely slice.
In the same pan, cook the leek on a medium-low heat with 1 tablespoon of oil for 15 minutes, or until soft and starting to colour, adding splashes of water if it looks dry.
Season with black pepper, then remove from the heat.
Meanwhile, bring a large pan of water to the boil and cook the gnocchi according to packet directions.
Drain, reserving a little of the cooking water.
Whisk the egg, Parmesan and a pinch of black pepper in a bowl.
Remove the leek from the heat, toss with the gnocchi and stir in the egg mixture along with a splash of cooking water to make a creamy sauce.
To serve, divide the gnocchi between two plates and sprinkle over the crumb.
Dress the salad leaves with extra virgin olive oil, sea salt and pepper, and serve alongside.
