Cut off and discard crusty ends of bread. Tear rest of loaf into bite size chunks. Arrange bread snugly in a heavily greased 13 x 9 x 2 inch baking dish. Set aside.
Cook mushrooms, 1 ½ teaspoons fresh oregano, and ¼ teaspoon pepper in butter in a large skillet over medium high heat, stirring constantly, until mushrooms are tender. Sprinkle mushroom mixture over bread. Pour white wine over mushroom mixture. Sprinkle with ham and next 3 ingredients.
Combine eggs and next 4 ingredients. Beat with a wire whisk until blended. Pour egg mixture over layers in dish. Cover and chill 8 hours.
Bake strata, covered, at 350°F for 45 to 50 minutes. Remove from oven, and spread with sour cream. Sprinkle with Parmesan cheese. Broil 4 inches from heat with electric oven door partially opened 2 to 3 minutes or until lightly browned. Garnish, if desired. Serve hot. 8 servings.
NOTE: If you’d like to omit the wine in this rich brunch dish, substitute 2/3 cup milk.