pasta gratin with tuna

ingredients:
400g penne pasta
200g broccoli florets detailed
2 cans of tuna, drained well
150 gr grated cheese
herbes de provence
For the cheese sauce
1 large onion, finely chopped
4 cloves garlic, grated
60 ml olive oil
70g flour
1/2 teaspoon salt spoon
1/2 teaspoon freshly ground black pepper 
100g cream cheese
750 ml milk
method:

Heat the olive oil in a saucepan.
Add onion and cook over low heat for 10 minutes, stirring occasionally.
Stir in the garlic and let it brown for ever one minute on low heat.
Add flour and melted cheese.
Add milk gradually, stirring constantly boiled with a whisk.
Add salt and pepper and let thicken over low heat.
In a pan put half a gratin of pasta.
Cover with half tuna and half of the cheese sauce.
Sprinkle with half the grated cheese and herbs de provence.
Put another layer of pasta, the rest of the tuna, broccoli and remaining sauce.
Sprinkle with grated cheese and broil made ​​for 15 to 20 minutes at 180 degrees.
http://www.bonoise-recettes.com/article-gratin-de-pates-au-thon-116922799.html