Potato, Leek and Fennel Gratin

I finally made this for Christmas dinner this year and it was over-the-moon fabulous.  In this recipe, caramelized leeks and fennel are layered with paper-thin russet potato slices, fresh thyme, cream and Swiss cheese and then slowly baked.  The result: rich, earthy flavors with an elegant spin.

I did some advance preparation.   I washed and sliced the fennel and leeks the day before and stashed them into Ziploc bags.  I also shredded the cheese and bagged it as well.  On Christmas morning, I thinly sliced the potatoes and kept them fresh in a bowl of cold water.

Christmas with Southern Living 2001
Page 148
Copyright:  Oxmoor House

2 large fennel bulbs
2 leeks
2 tablespoons butter
3/4 teaspoon salt
1 teaspoon chopped fresh thyme
2 pounds baking potatoes, peeled and thinly sliced
2 tablespoons all-purpose flour
1/2 teaspoon salt
3/4 cup whipping cream
2/3 cup milk
3 cups shredded Gruyere or Swiss cheese
2 teaspoons chopped fresh thyme, divided
1/4 teaspoon freshly ground pepper

Rinse fennel.  Trim stalks to within 1" of the bulb.  Discard stalks and fronds.  Cut a slice off the bottom of the bulbs.  Slice lengthwise in half.  Remove core with a paring knife.  Cut the fennel into 1/4" slices.

Rinse leeks.  Trim off the root ends and tops from leeks, leaving 1" of dark leaves.  I sliced the leeks into 1/4" thick disks and added them to a bowl of cold water, separating the rings.  Swish them around and the grit will fall to the bottom.  Drain the leeks well and dry them on paper towels.

Saute the fennel and leeks in the butter in a large skillet over medium-high heat for five minutes.  Add the 3/4 tsp. salt and 1 tsp. thyme.   Cover, reduce heat to medium-low and cook for 10 more minutes.  Set aside.

Combine potato slices, flour and 1/2 tsp. salt in a large zip-top bag.  Seal the bag and shake to distribute the flour and salt.   Arrange half the potato in a buttered gratin dish or 13" x9" dish.

Combine whipping cream and milk; pour half of this mixture over the potatoes in the dish.  Sprinkle with 1 1/2 cups cheese and 1 tsp. thyme.  Spoon all the caramelized fennel and leeks over this and top with remaining potato slices.  Pour the remaining cream mixture over this and sprinkle with remaining cheese, 1 tsp. thyme and pepper.

Bake, covered, in a preheated 400 degree oven for 45 minutes.  Uncover and bake for 15 more minutes or until golden and bubbly.  Let stand 10 minutes before serving.