Ingredients:

1 tbsp unsalted butter
1 tbsp flour
1 cup chicken broth
Salt
Black pepper
1/2 tsp freshly milled black pepper
1/2 tsp freshly grated nutmeg
2 tbsp olive oil
3 tbsp unsalted butter
1 cup thinly sliced spring onions
200 g thinly sliced prosciutto, diced
250g thinly sliced, trimmed mushrooms
250 g penne pasta
1/2 cup freshly grated parmesan cheese
2 tbsp minced parsley leaves

Preparation:

1 – In a largish saucepan, melt 1 tbsp butter over low heat. When butter begins to froth, add the flour. Mix well with a wire whisk and cook over medium heat, stirring constantly, until lightly golden. Add chicken broth, 1/2 tsp salt, 1/2 tsp pepper and nutmeg. Turn heat to low and cook, whisking constantly, until slightly thickened, about 2 minutes. Cover saucepan and set white sauce aside.

2 – In a large sauté pan, heat olive oil over medium heat until haze forms, then add 2 tbsp butter. Add onions and cook, stirring constantly, until barely tender, about 1 minute. Stir in prosciutto and cook, stirring, until softened but not brown, about 1 minute. Add mushrooms, turn heat to medium-high and cook, stirring, until mushrooms just begin to exude their juices, about 1 minute. Season with salt and pepper. Pour white sauce over mushroom mixture and blend well. Turn heat to low and cook, stirring, until mixture is well incorporated, about 2 minutes. Remove from heat.

3 – Cook pasta in 6 litres boiling water with 1 tbsp salt until al dente. Drain in a colander, transfer to a bowl containing 1 tbsp softened butter and toss quickly. Mix 3/4 of the sauce and parmesan cheese with pasta. Spoon the remaining sauce over pasta and garnish with minced parsley. Serve with additional freshly grated parmesan cheese.