Preheat oven to 425 degrees. Lightly grease two 6-ounce ramekins with butter and sprinkle with a little bit (1/2 teaspoon) of sugar.
In a mixing bowl, use a hand mixer to whip together Nutella, heavy cream, egg yolk, vanilla extract, and a pinch of salt. Mix until smooth.
Pour egg whites into the bowl of a stand mixer. Whip on a high speed. Gradually poor in 1 tablespoon sugar while whipping. Continue to whip until stiff peaks form.
Pour egg whites over Nutella mixture. Gently fold together. Once it is almost completely incorporated, fold in crumbled bacon.
Pour batter into prepared ramekins.
Bake in the center of the preheated oven for 15 minutes. Serve immediately.