Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan thoroughly. In a large bowl, combine the German chocolate cake mix, instant chocolate pudding mix, 4 large eggs, 1 cup milk, 1/2 cup vegetable oil, and 1 teaspoon vanilla extract. Beat with an electric mixer on medium speed for 2 minutes, until smooth and well combined. Pour the batter evenly into the prepared baking pan.
Step 2: In a separate medium bowl, beat the softened cream cheese with 1/2 cup granulated sugar, 1 large egg yolk, and 1 teaspoon vanilla extract until smooth and creamy. This is your cheesecake swirl mixture.
Step 3: Drop spoonfuls of the cream cheese mixture over the chocolate cake batter in the pan. Don't worry about being too neat – the 'earthquake' effect thrives on randomness! Then, sprinkle the sweetened shredded coconut and chopped pecans evenly over the entire cake batter surface.
Step 4: Bake for 40-45 minutes, or until a wooden skewer or toothpick inserted into the chocolate cake portion (not the cream cheese) comes out clean. The top will be golden brown and appear cracked – this is the desired 'earthquake' look! Let the cake cool in the pan for about 10-15 minutes while you prepare the glaze.
Step 5: For the glaze, in a medium saucepan, combine 1 cup unsalted butter, 1 cup granulated sugar, and 1/2 cup evaporated milk. Bring to a boil over medium heat, stirring constantly. Reduce heat and simmer for 2 minutes, still stirring. Remove from heat and stir in 1 teaspoon vanilla extract. If using, stir in the chocolate chips until melted and smooth.
Step 6: While the cake is still warm (but slightly cooled from the oven), generously pour the warm glaze evenly over the entire cake, allowing it to seep into the cracks. Let the cake cool completely before slicing and serving. The glaze will set slightly as it cools. For best results and flavor, allow it to chill for at least 2 hours, or overnight, before serving. You can store any leftovers in an airtight container for up to 3-4 days.