Ingredients
| 1 1/2 lbs | (750 g) | Yukon Gold potatoes |
| 1 1/2 lbs | (750 g) | sweet potatoes |
| 2 cups | (500 ml) | 2% milk |
| 1/4 cup | (60 ml) | butter |
| 2 | cloves garlic, minced | |
| 2 tbsp | (30 ml) | fresh herbs, minced |
| 1/2 tsp | (2 ml) | salt |
| 1/2 tsp | (2 ml) | pepper |
| 1 1/2 cups | (375 ml) | grated Gruyére cheese |
Directions
- Wash both types of potatoes then peel and cut into 1/8-inch-thick (0.3 cm) rounds. Place cut potato slices in a bowl of cold water to prevent browning.
- Combine milk, butter, and garlic in a medium saucepan. Simmer for 5 minutes. Remove from heat. Add salt, pepper, & herbs. Stir gently.
- Butter a 13x9x2-inch (33x22x5-cm) glass baking dish. Drain potatoes really well. Layer half of Yukon Gold and half of sweet potato rounds in bottom of baking dish. Top with half of milk mixture and half of grated cheese. Repeat.
- Preheat oven to 400F (200C). Cover gratin tightly with aluminum foil. Bake 45 minutes. Remove foil and bake another 15-30 minutes until gratin is golden and sauce is well absorbed.
- Let stand 10 minutes and serve.