Jacques Pepin Maman's Cheese Souffle

I want to try this "easy" souffle from Jaques Pepin's memoir.

6 T butter, plus more to butter a 6 cup gratin dish
6 T all-purpose flour
2 c cold milk
1/2 t salt
1/2 t pepper
5 extra large eggs
2 1/2 c grated Gruyere (6 oz)
3 T minced chives

Preheat oven to 400.  Butter a 6 cup gratin dish, and set it aside.  Melt the butter in saucepan and add flour.  Mix in well with a whisk.  Cook 10 seconds, add milk all at once and whisk.  Keep stirring until mixture thickens and comes to a strong boil (about 2 minutes).  Remove from heat and stir in salt and pepper.  Allow sauce to cool for 10 minutes. Meanwhile, break eggs into a bowl and beat well.  Add eggs, cheese, and chives to the cooled sauce.  Mix well to compne.  Pour into butter gratin dish and cook immediately.  Boake 30 to 40 minutes, or until souffle is puffy and well browned on top.  Best served right away.