Butter 6 small ramekins or ovenproof coffee cups.

Dust each with bread crumbs. (This helps the soufflé to have something to “grab” onto as it rises.) Preheat the oven to 375°F.

Peel the parsnips and cut into 2-inch lengths. Cook in a large pot of boiling salted water until tender, 15 to 20 minutes. Drain thoroughly.

Transfer the parsnips to a food processor and cool slightly, about 15 minutes, with the lid of the processor removed. Add the butter, milk, and flour. Puree until smooth.

Add the egg yolks, cheese, rosemary, and salt. Process to thoroughly combine. Transfer the mixture to a large mixing bowl and set aside.

In the bowl of an electric mixer, whip the egg whites until stiff. Carefully fold the whites into the parsnip mixture in 3 batches.

Divide the mixture among the prepared ramekins. Place the ramekins on a baking sheet. Bake for 30 minutes until puffed and slightly golden. Serve immediately.