Leek and Potato Au Gratin
Preheat oven to 350 F. Butter the inside of a 2-quart baking dish. In a sauté pan, heat olive oil and butter over medium heat until butter foams. Add leeks and fennel and sauté for 15 minutes, until tender. Mix potatoes in a large mixing bowl with the cream, salt and pepper. Add cooked fennel and onion and stir to combine. Pour contents into baking dish. Top with cheese. Bake for 1-1/2 hours or until potatoes are tender and top is browned and bubbly.