Mashed Potato Soufflé (French Pommes de Terre Mont d’Or)

Seasoned with garlic and lightened with egg whites, a potato soufflé is delightfully puffy out of the oven.

4 cups mashed potato, leftover or fresh
3 eggs
½ cup Gruyère or Swiss cheese, shredded
¼ tsp. kosher or sea salt
black pepper, freshly ground
1 Tbsp. Parmesan cheese, grated
butter, for greasing the gratin dish

Preheat oven to 400°F (200°C/180°C fan, Gas Mark 6). Butter a shallow gratin, baking or casserole dish.

Put the mashed potatoes in a large bowl. Add the eggs, Gruyère, salt and pepper. With a whisk, whip all the ingredients together.

Scoop potatoes into the prepared gratin dish and smooth with a spatula. Scatter the Parmesan cheese over the top and place on a baking sheet (in case of spills) in the lower part of the oven.

Bake about 30-35 minutes, until the top of the gratin is crusty and golden.