Bake:20 mins to 25 mins 375°F or bake for 35 to 40 minutes for souffle dish
Bring large pot of water to a boil. Add spinach and scallion, stirring and submerging; cook about 2 minutes or until wilted. Drain well. When cool enough to handle, squeeze out excess water. Finely chop.
In medium-size saucepan, melt butter over medium heat. Sprinkle with 3 tablespoons flour; whisk about 1 minute or until blended and cooked slightly. Add milk, whisking to prevent lumps. Cook over medium heat about 3 minutes or until mixture reaches a low boil, whisking in 1 teaspoon salt, the nutmeg and cayenne pepper. Remove saucepan from heat. Whisk in cheese; let cool slightly.
Heat oven to 375 degrees . Lightly coat eight (7-ounce) oval baking dishes or one 10-cup oval or souffle dish with nonstick cooking spray. Sprinkle with bread crumbs, tilting dish to coat.
In large bowl, whisk half of the cheese mixture into egg yolks. With wooden spoon, vigorously stir in remaining cheese mixture and the spinach mixture.
In large clean bowl with electric mixer on medium to high speed, beat together egg whites, lemon juice and remaining 1/4 teaspoon salt until stiff peaks form. Sift remaining 3 tablespoons flour over egg whites and gently fold in. Stir one-quarter of beaten egg whites into spinach mixture to lighten. Gently fold in remaining egg whites. Spoon about 1 cup into each 7-ounce dish or scrape whole amount into souffle dish. Place individual dishes on baking sheet.
Bake individual souffles at 375 degrees about 25 minutes or until golden brown and puffed (or bake for 35 to 40 minutes for souffle dish). Serve immediately.