Homemade Scalloped Potatoes with Cheese

Bahan-bahan (12 porsi)

• 1/4 cup butter ((1/2 stick))
• 1 onion (thinly sliced)
• 1 tablespoon kosher salt
• 1/4 teaspoon black pepper
• 1/4 teaspoon cayenne pepper
• 1/4 teaspoon dried thyme
• 5 cloves garlic (smashed and minced)
• 6 tablespoons flour
• 4 cups heavy cream*
• 1/2 cup parmesan cheese (shredded)
• 4 pounds russet potatoes** (peeled and sliced to 1/8 inch)
• 3 cups sharp cheddar cheese (shredded and divided in half)