Put the milk and 1-1/4 cups of the corn kernels in a blender. Blend until puréed. Strain the purée through a medium-fine sieve, using a rubber spatula to push through as much pulp as possible; you’ll have about 1-1/2 cups purée.
In a heavy-based saucepan, melt the butter over low heat. Whisk in the flour and cook for a minute, still whisking. Slowly whisk in the corn purée and whisk over medium-low heat until the mixture becomes as thick as pudding, 3 to 5 minutes. Pour into a large bowl and let cool to room temperature.
Heat the oven to 400°F. Generously butter six 6-ounce ramekins.
When the soufflé base is cool, stir in the egg yolks, the remaining 3/4 cup corn kernels, salt, pepper, and chives. In a clean, dry bowl, beat the egg whites until they form soft peaks. Working quickly, use a rubber spatula to gently stir half of the whites into the soufflé base and then fold in the rest. Fill the ramekins just over three-quarters full and set them in a baking dish large enough to hold all the ramekins. Pour enough hot water into the baking dish to come halfway up the sides of the ramekins. Bake the puddings until they’re puffed, set, and golden brown, about 30 minutes; rotate the pan once during baking.
A hot-water bath bakes the soufflés evenly. They're done when they're puffed, set, and golden brown.
Remove the puddings from the baking dish and let cool for about 15 min. Unmold the puddings by sliding a knife around the edge of each ramekin and gently inverting the pudding into the palm of your hand. Set the puddings browned side up in an oval gratin dish; they should be close but not touching. (For a more elegant presentation, you can put them in individual gratin dishes.)
The soufflés deflate as they sit, which is fine. Once they've cooled, slide a knife around the edge of each ramekin to loosen the soufflé.
The sunken, cooled soufflés should fall right out. Set them right side up in one large gratin dish or in six small ones.
When ready to serve, heat the oven to 400°F. Pour the heavy cream over and around the puddings and heat them in the oven until the cream bubbles and the puddings repuff slightly, about 10 min.
Just before serving, pour on a little heavy cream and bake just long enough to let the puffings puff slightly again.
After the first baking, soufflés can be unmolded and arranged in their gratin dish(es) one day in advance; cover lightly with plastic wrap and refrigerate. Pour the heavy cream over the puddings and bake them the second time just before serving.