- In a large skillet melt butter over medium heat. Add mushrooms and leeks; cook 5 minutes or until tender, stirring occasionally. Remove from heat. Stir in parsley and pepper.
- Line a 6-quart slow cooker with a disposable slow cooker liner. Place bread cubes prepared cooker. Add vegetable mixture. Drizzle with enough broth and white wine to moisten, tossing lightly.
- Cover and cook on low for 3 1/2 to 4 hours. If desired, gently stir in walnuts. If needed, stir in enough additional warmed broth to reach desired consistency
From the Test Kitchen
To make dry bread cubes, cut fresh bread into 1/2-inch cubes. (18 to 21 bread slices will yield 12 cups cubes). Preheat oven to 300 degrees F. Spread cubes in two 15x10-inch baking pans. Bake 10 to 15 minutes or until dry, stirring twice; cool. (Cubes will continue to dry and crisp as they cool.) Or let bread cubes stand, loosely covered, at room temperature for 8 to 12 hours.