Spinach Cheese Soufle

~ 1 table spoon olive oil
~ 1 small onion chopped
~ 1 - 12 ounce baby spinach
~ 1/4 cup butter
~ 1/4 all purpose flour
~ 1 1/2 cups milk, warmed
~ 1/4 teaspoon dry mustard
~ 1/4 teaspoon ground red pepper

~ 5 large eggs, at room temperature, separated

Heat oven to 350 degrees F. Butter a 2-quart souffle dish.  


In Medium Saucepan, heat oil. Add onion and cook about three minutes until softened and translucent. Add spinach and stir two minutes or until wilted. Let cool. Squeeze out excess liquid and chop.


In a medium Saucepan over medium heat melt butter and whisk in the flour to combine. Slowly add the milk, whisking constantly, to combine. Bring to a boil and cook two minutes.


Remove From heat and stir in cheese, mustard, and pepper to combine. Transfer to a medium large bowl.


Beat egg whites to firm peaks. Stir 1/3 of the whites into the cheese mixture. In two additions, fold in the remaining whites.


Bake 55 to 60 minutes until wooden skewer one inch from the edge comes out clean and souffle is fully raised. Served immediately.