Step 1Heat the oven to 350 degrees. Combine the flour, sugar and salt in a medium mixing bowl.
Step 2Beat the egg yolks in a second bowl. Add the milk, lime zest and juice and stir into the dry ingredients, mixing well to make a smooth batter.
Step 3In a clean bowl, whip the egg whites until stiff peaks form. Using a rubber spatula, gently but thoroughly fold them into the batter. Transfer to a souffle dish or 1-quart casserole. Place in a larger baking dish and pour hot water into the larger dish to a depth of about 1 inch.
Step 4Bake 50 minutes. Serve warm or cold, ladling the top and sauce onto dessert plates.