- 1 tablespoon olive oil
- 1 small onion, chopped
- 1-12 ounce bag of baby spinach
- 1/4 cup butter
- 1/4 cup all-purpose flour
- 1&1/2 cups milk, warmed
- 1/2 pound cheddar cheese, grated
- 1/4 teaspoon dry mustard
- 1/4 teaspoon ground red pepper
- 5 large eggs, at room temperature, separated
- Heat oven to 350 degrees. Butter a 2-quart souffle dish.
- In a 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 soufflé is fully raised. Serve immediately.
Cooking Time:55 to 60 minutes
Ready In:65 minutes
Egg whites are beaten stiff when a peak holds without its tip bending, and when the bowl is tilted the whites do not slide out.