INGREDIENTS
1 1/2 lb
red-skinned sweet potatoes
1 lb
Yukon Gold potatoes
1/2 cup
heavy cream
1/2 cup
whole milk
1 1/2 tbsp
butter, (divided)
1 tsp
minced garlic
1 tbsp
chopped fresh thyme
1/2 tsp
fine ground sea salt
Freshly ground black pepper, (to taste)
1 cup
grated Gruyère cheese
1/4 cup
finely shredded Parmesan cheese