Clean leeks and cut them, the white and most of the green, in 1/2-inch (1 cm) lengths.
Place the butter in a 6-cup microwave-safe dish and melt 3 minutes at HIGH.
Add the leeks, stir until well buttered.
To cook the small egg noodle shells, measure 6 cups (1.5 L) water in a large microwave-safe dish.
Microwave 6 minutes at HIGH.
Add the noodles.
Microwave 5 minutes at HIGH.
Drain, add to the melted leeks.
Add salt and pepper to taste.
Microwave 1 minute at HIGH.
Serve as soon as ready with a bowl of grated cheese.