Savory Leek & Gruyère Soufflé | Williams Sonoma

Ingredients

• 2 Tbs. unsalted butter, softened, plus 5 Tbs. cold unsalted butter
• 2 cups grated Gruyère cheese
• 2 Tbs. olive oil
• 4 leeks, about 1 1/2 lb. total, trimmed and chopped
• 1 tsp. chopped fresh thyme
• Salt and freshly ground pepper, to taste
• 5 Tbs. all-purpose flour
• 2 1/2 cups half-and-half, warmed
• 6 eggs, separated