Ingredients
- 3 Tbsp butter, divided
- 3 medium leeks, thinly sliced
- 2 cloves garlic, minced
- 2 Tbsp all purpose flour
- 11/2 cups whole milk
- 1/2 tsp salt
- 1/4 tsp black pepper
- 1/4 tsp dry mustard powder
- 2 sprigs fresh thyme (1/2 tsp dried)
- 3 large red or white potatoes (1 lb), thinly sliced (1/8 inch)
- 2 large carrots, thinly sliced (1/8 inch)
- 11/2 cups shredded melting cheese (cheddar, gruyere, Swiss, Fontina, mozzarella)
- 1 Tbsp fresh chopped chives or parsley to garnish
Instructions
- Preheat oven to 375°F/ 190°C and generously grease or butter a 21/2 quart/litre baking dish.
- In medium pan, sauté leeks in 1 Tbsp butter until tender, about 5-7 minutes.
- Add garlic and sauté another 1-2 minutes.
- Remove leeks from pan and set aside.
- In same pan, melt remaining 2 Tbsp butter.
- Mix in flour until all of the butter is absorbed.
- Gradually whisk in milk to make a smooth sauce.
- Add salt, pepper, mustard powder and thyme. Stir and heat until sauce is thick and smooth. Taste and adjust seasoning to your liking. Remove from heat.
Assembly & Baking
- Layer the gratin in prepared dish in thirds. Start with 1/3 potatoes, leeks, carrots, top with 1/3 cheese, top with 1/3 sauce. Repeat two more times finishing with sauce.
- Bake, covered for 30 minutes. Uncover and bake another 25 to 30 minutes until vegetables are tender. To test tenderness, insert a knife through layers.
- Remove from oven and let rest for 10 minutes to set. Garnish with fresh chives or parsley.
Notes
Want to change the cheese – go for it! Use your favourites.
Want to skip the carrots – no problem. Make this gratin the way you want!
Want to add a layer of bread crumbs and parmesan on top – that would be mighty tasty and a classic au gratin touch.