Position a rack in the center of the oven and preheat to 425º.
Grease the ramekins with 1 tablespoon of the butter, and coat evenly with 2 tablespoons of the parmesan. Place on a rimmed baking sheet and set aside.
Place the chopped green garlic and spring onions in a large bowl and soak in cool water for a few minutes, swishing occasionally to loosen any sand or dirt that might be hanging on.
Meanwhile, heat a large skillet over a medium-high flame. Melt 1 tablespoon of the butter, then lift the alliums out of their soaking water, shake off excess water, and toss them in the pan. Reduce the heat to medium, add a few pinches of salt and the lemon zest, and cook, stirring occasionally, until tender but not browned, 10 minutes or so. Add the lemon juice and remove from the heat. Let cool slightly.
Make the bechamel:
Melt the remaining 3 tablespoons of butter in a small saucepan over medium heat. Add the flour and cook, stirring, for a minute, then whisk in the milk. Bring the mixture to a simmer, whisking constantly, and cook for a few more minutes until thickened. Remove from the heat and add 3/4 teaspoon salt. Let the bechamel cool slightly, stirring occasionally to prevent a skin from forming.
Have the egg yolks in a large bowl, and slowly whisk in the slightly cooled bechamel. Stir in the cheese, alliums, the remaining 1/4 cup of parmesan, and the chives.
In a second large, clean bowl (or the bowl of a stand mixer) whip the whites with a pinch of salt until soft peaks form. (This means that when you lift the beater out of the bowl and turn the beater upside down, a peak of egg white should flop over.) Use a large, rubber spatula to immediately stir 1/3 of the egg whites into the souffle batter until almost combined, then gently fold in the remaining egg whites just until no streaks or lumps of egg white remain.
Divide the batter among the ramekins, filling them 1/4-1/2" from the top. Place in the oven and turn the temperature down to 400º. Bake for 20-25 minutes, opening the oven as infrequently as possible, until the souffles are puffed and nicely browned. (The baking time will be longer for 1 large souffle, maybe 35-45 minutes.)
Serve immediately from the oven. If you have extras, cool and store in the fridge for up to a few days. The souffles reheat beautifully, even puffing up a second time, though not as high, in a 350º oven or toaster oven.
You can either bake these individually, in 2-cup ramekins, or in one large gratin dish. I used a mild dutch goat gouda in these souffles, but gruyere, cheddar or a fresh goat cheese would all be good, too. Other herbs could be added with or in place of the chives.You can use the two leftover egg yolks to make a half batch of ice cream, creme caramels, or try Heidi Swanson's awesome tapioca pudding.Nutritional values are based on one of five servings.