Preheat oven to 375 degrees. Butter a 1 1/2-quart souffle dish or 6 (1-cup) ramekins and sprinkle with 1 tablespoon of the Parmesan cheese. Set aside.
In a medium skillet, melt 1 tablespoon of the butter over medium heat. Add the green onions and saute until wilted. Add the spinach, herbs, and a pinch each of salt and pepper. Cook, stirring frequently, until the moisture evaporates. Remove from the heat and reserve.
In a small saucepan heat the milk over medium heat until small bubbles form around the edges.
In a medium saucepan, melt the remaining 3 tablespoons of butter over medium-high heat. Stir in the flour and whisk until a smooth paste forms, about 2 minutes. Do not allow the flour to brown. Whisk in the hot milk, a pinch of salt, and a dash of hot sauce. Cook, stirring, until the mixture boils and thickens, about 2 minutes. Remove from the heat and beat in the egg yolks one at a time. Fold in the spinach mixture and stir in all but 1 tablespoon of the remaining Parmesan cheese.
Put egg whites and a pinch of salt in the bowl of an electric mixer. Beat until stiff peaks form. Stir a large spoonful of the egg whites into the spinach mixture to lighten it, then fold in the remaining egg whites just until combined. Spoon the mixture into the prepared souffle mold or ramekins. Sprinkle the top with the remaining cheese. Bake until puffed and golden, about 30 to 35 minutes for the large souffle or 15 to 20 minutes for the small ones. Serve immediately.