Mississippi Mud Pie

Name: Mississippi Mud Pie
Prep time: 45 min
Cook time: 40 min
Total time: 6 h
Yield: 10
Ingredients: Ingredients; 24 chocolate sandwich cookies (like Oreos), crushed; 4 tablespoons unsalted butter, melted; 1/2 cup unsalted butter, softened; 1 cup granulated sugar; 4 large eggs; 1/3 cup unsweetened cocoa powder; 1/2 cup all-purpose flour; 1/4 teaspoon salt; 1 teaspoon vanilla extract; 1 1/2 cups mini marshmallows; 1 box (3.9 oz) chocolate instant pudding mix; 2 cups cold whole milk; 1 1/2 cups heavy whipping cream; 3 tablespoons powdered sugar; 1/2 cup chopped pecans (optional); 1/4 cup chocolate shavings for garnish