Name: Creamy Scalloped Potatoes with Thyme
Prep time: 30 min
Cook time: 90 min
Total time: 120 min
Yield: 6
Ingredients: 3 tablespoons + 1 teaspoon butter (divided); 3 tablespoons flour; 1 teaspoon dry mustard; 1 teaspoon kosher salt; 2 cups milk; 1/2 teaspoon black pepper (freshly ground); 1 tablespoon thyme leaves (chopped fresh); 2 pounds yukon gold potatoes (peeled and thinly sliced crosswise); 1 medium onion (diced)