Ingredients :

• Potatoes — Choose waxy varieties—like Charlotte or Monalisa. They hold up well during cooking and won’t turn into mush at the bottom of the dish. Avoid floury varieties like Bintje: too much starch makes it sticky and prone to falling apart.
• Ground beef — 15% fat content, no less. Beef that is too lean results in dry, grainy meat that has no appeal once cooked. Fat is what provides the flavor and binds the layers during baking.
• Broth — A beef or vegetable bouillon cube diluted in 25 cl of hot water is perfect. This is what will cook the potatoes from the inside and give them depth. Without liquid, the bottom layers remain hard and starchy.
• Cheese — Grated Emmental for a classic touch, Comté for more character, or even Cheddar if you want a more orange and savory crust. Be generous. It’s the part everyone looks at when it comes out of the oven.