In a medium skillet heat two tablespoons of butter over medium high heat until it is melted. Add in the leeks and cook for 7-8 minutes or until they begin to soften. Add in the garlic and cook for 2 minutes.

Remove the leeks and garlic to a plate.

Add the remaining butter and melt. Add the flour and whisk constantly until the flour begins to turn pale yellow, about 2 minutes.

Slowly add in the milk, whisking constantly.

Cook for 5-7 minutes, whisking frequently, until the mixture has thickened.

Add in 1 1/4 cup cheese and mustard. Stir until cheese has melted.

Stir in the leeks, garlic, peas, salt, pepper, and oregano. Cook for one minute.

Stir in the gnocchi.

Sprinkle with additional 1/4 cup of cheese and put in the oven. Broil for 2-3 minutes.