Three-Cheese Potatoes | Mama's Cooking

Ingredients

• 3 tablespoons butter, plus more, to taste, for greasing the pan
• 2 cloves garlic, minced
• 3 tablespoons all-purpose flour
• 2 cups whole milk
• 1 1/4 cups cheddar cheese, shredded, divided
• 3/4 cup Gruyère cheese, shredded, divided
• 1/4 cup plus 2 tablespoons parmesan cheese, grated, divided
• 1 teaspoon dry mustard
• 1/4 teaspoon dried thyme
• 1/4 teaspoon paprika
• salt, to taste
• black pepper, to taste
• 1 1/4 pounds red potatoes, washed and unpeeled, thinly cut
• 1 1/4 pounds Yukon Gold potatoes, washed and unpeeled, thinly cut
• 1 onion, thinly sliced
• chives, to taste, for garnish
• parsley, to taste, for garnish