190°C. Apply a 23×33 cm glass baking sheet with 1 tablespoon of butter or baking spray. Put it aside.
In a large frying pan, melt over medium heat 2 tablespoons tter. Add the slior in a large measuring cup with a spout, beat the cream, 1 cup grated Parmesan, the remaining 1 teaspoon of salt, black pepper and chopped thyme. Stir in the warm caramelized onion until everything is well combined. This is your only creamy dressing.
Preparation of potatoes: Peel the potatoes if you wish (you can
