3 tbsp butter + extra to grease pie plate
4 cloves garlic, minced
1 leek, white and light green parts, minced
4 cipolini onions, minced
2 tbsp tarragon, + 1 tbsp finely chopped, for garnish
3 cups heavy cream
2 lb butter potatoes, unpeeled and sliced 1/8 inch thick
Salt and pepper to taste
Preheat oven to 350F Butter a 9 inch glass pie plate.
Combine 3 tbsp butter, garlic, leek and onions in a saucepan. Place on medium low heat and saute until mixture is light golden, about 15 minutes. Add 2 tbsp tarragon, cream and potatoes and mix well. Simmer until potatoes are varely cooked, about 15 minutes. Season with salt and pepper to taste.
Transfer potatoes carefully to a pie plate, spread evenly and pressing to compact. Drizzle with 2-3 tbsp of cream and cover with foil. Bake for 40 minutes, then remove foil and cook an additional 10 minutes more and golden brown. Remove from heat and rest for 15 minutes. Garnish with tarragon and serve.