Wrap baking parchment around four small soufflé dishes and secure with string. Grease with butter, and with half of the Parmigiano Reggiano, coat the base and sides of each.
Melt 70g butter in a pan and stir in flour. Whisk in milk until sauce thickens.
Stir through Gorgonzola, remaining Parmigiano Reggiano and black pepper.
Whisk in egg yolks, one at a time and set aside.
Whisk egg whites to stiff peaks. Stir 2 tbsp into the Gorgonzola sauce, then fold in the rest of the egg whites until combined. Do not over mix.
Bake for 20-30 minutes, until risen and golden brown. Serve as soon as soufflés are removed from the oven.