INGREDIENTS
1
Shallot
1 tsp
Thyme, fresh
3 lb
Yukon gold potatoes
1/2 cup
Chicken stock
2 tbsp
All-purpose flour
1
Salt and freshly ground pepper
1 tbsp
Butter, unsalted
1 cup
Gruyere cheese, grated
1/2 cup
Heavy cream
1/2 cup
Parmigiano-reggiano cheese, grated