Molten Chocolate Crackle Pie

Name: Molten Chocolate Crackle Pie
Prep time: 20 min
Cook time: 1 h 15 min
Total time: 1 h 35 min
Cuisine: European, American, Mediterranean
Ingredients: 1 pie crust round ((homemade recipe below)); 1 egg, beaten, for brushing; vanilla sugar or coarse sugar, for sprinkling ((optional)); 4 large eggs; 1 1/2 cups granulated sugar; 1/2 cup unsweetened cocoa powder; 2 teaspoons instant coffee granules; 1/2 teaspoon kosher salt; 10 tablespoons salted butter, melted; 1 tablespoon hazelnut liquor ((optional)); 2 teaspoons vanilla extract; 1/2 cup semi-sweet chocolate chips or chunks; 1 cup heavy cream; 1 tablespoon real maple syrup; 2 teaspoons vanilla extract; 1 tablespoon hazelnut liquor ((optional))