Beefsteak Bigarade

1 medium orange
2 trimmed shell or strip steaks, cut 1/2 inch thick 5 to 6 ounces each
1 garlic clove, halved
1/4 teaspoon salt
1/8 teaspoon freshly ground pepper
1 tablespoon unsalted butter
1 tablespoon olive oil
1 tablespoon minced shallot
2 tablespoons ruby port
1 teaspoon Cognac or brandy
1/2 teaspoon Dilon-style mustard
Watercress and thin slices of orange, for garnish

1. Remove the zest from one-quarter of the orange. Cut into thin slivers. Place in a small bowl and cover with 3/4 cup boiling water. Drain and pat dry on paper towels. Halve the orange and squeeze 1/2 tablespoon of juice into a small bowl. Reserve the unsqueezed orange half.

2. Place each steak between 2 pieces of waxed paper and pound until about 1/4 inch thick. Rub both sides with the cut garlic and the cut side of the reserved orange half. Season each with half of the salt and pepper.

3. In a large heavy skillet, melt the butter in the oil over moderately high heat until sizzling. Add the steaks and cook until lightly browned on the bottom, about 1 1/2 minutes. Turn and cook on the second side until lightly browned and medium-rare, about 30 seconds. Remove from the skillet and cover loosely with foil to keep warm.

4. Over low heat, stir in the shallot, port, Cognac, mustard, reserved orange juice, slivered orange zest and 2 teaspoons of water until blended. Cook,scraping up any brown bits from the bottom of the skillet, until the sauce is slightly reduced, about 1 minute. Spoon the sauce over the steaks and serve garnished with the watercress and orange slices.