Preheat the oven to 350°F (175°C) and grease 4 ramekins with a generous amount of butter.
Melt the butter in a small saucepan over low heat. Add the grated chocolate, remove from the heat, and whisk well to melt and combine. Set aside.
Using an electric mixer, beat the eggs until fluffy, for about 5 minutes.
Combine the chocolate mixture with the eggs. Fold in the flour, Erythritol, and salt.
Pour the mixture into the prepared ramekins and bake for 7-10 minutes. The edges should be set, but the center at the top should still be jiggly.
Remove from the oven and turn out onto serving plates. Optionally garnish with low carb fruit and serve hot.