Melt the butter in a pan and sauté the shallots and celery for 2-3 minutes. Then add the rice, stir well and deglaze with the champagne. Bring to the boil while stirring constantly.
Gradually add the stock (in approx. 3 steps) and let it boil down until the next portion is added (approx. 20 minutes depending on the type of rice).
Mix in the parmesan and butter, season with salt and pepper, remove the pan from the fire and let everything rest for approx. 1 minute: refine each portion with a dash of champagne immediately before serving.