Preheat oven to 400°F. Grease 4 8-ounce ramekins liberally with 1 tablespoon of the unsalted butter. Set atop a baking sheet that has been lined with parchment paper or aluminum foil and set all aside.
Heat remaining unsalted butter in a large saucepan over medium heat just until butter foams. Add the shallot and spring onions and cook, stirring occasionally, until softened, about 5 minutes.
Add 2 cups water, heavy cream, whole milk, and Kosher salt to the shallot and onion mixture and bring to a boil over medium-high heat. Do not walk away from the stove at this time, as the mixture is prone to boil over.
Reduce heat to medium-low and whisk in the grits all at once. Cook until thickened, whisking intermittently to prevent scorching on the bottom, about 20 minutes. Remove from heat and whisk in the goat cheese until completely melted.
While grits cook, whisk together egg yolks and Dijon in a medium bowl. Set aside. Beat egg whites with whisk attachment in the bowl of a stand mixer or with an electric hand mixer on medium-high speed until soft peaks form, 2 to 3 minutes. See recipe card below for cooking at high altitude.
Whisk ¼ cup of the hot grits into yolk mixture to temper, then whisk tempered yolk mixture into remaining grits until combined. Gently fold one-third of the egg whites into grits and repeat until all whites are folded into grits.
Divide mixture equally among prepared ramekins. Bake in preheated oven until puffed and set but still slightly jiggly in centers, about 15 minutes. Garnish however desired. Serve immediately!