Step 1: Preheat your oven to 375°F (190°C). Grease and flour a 13x18-inch jelly roll pan.
Step 2: In a large saucepan, combine the water, 1/2 cup butter, and 1/4 cup unsweetened cocoa powder. Bring to a boil over medium heat, stirring until the butter is melted and the cocoa is dissolved. Remove from heat.
Step 3: In a large mixing bowl, whisk together the flour, granulated sugar, baking soda, and salt.
Step 4: Pour the warm chocolate mixture into the dry ingredients. Stir well until just combined.
Step 5: In a separate small bowl, whisk together the buttermilk, eggs, and 1 teaspoon vanilla extract. Add this to the chocolate batter and stir until smooth. Do not overmix.
Step 6: Pour the batter evenly into the prepared jelly roll pan. Bake for 20-25 minutes, or until a wooden skewer inserted into the center comes out clean.
Step 7: While the cake is baking, prepare the fudge frosting: In a medium saucepan, combine 1/2 cup butter, 1/4 cup unsweetened cocoa powder, and 1/4 cup milk. Bring to a boil over medium heat, stirring occasionally. Remove from heat.
Step 8: Add the powdered sugar and 1 teaspoon vanilla extract to the hot frosting mixture. Whisk vigorously until the frosting is smooth and glossy. Work quickly as it sets fast.
Step 9: Immediately pour the warm fudge frosting evenly over the warm cake, spreading gently with an offset spatula if needed.
Step 10: While the frosting is still wet, generously sprinkle the toasted pecan pieces over the entire cake.
Step 11: Drizzle the caramel sauce decoratively over the cake. Allow the Turtle Texas Sheet Cake Recipe Fudge Caramel Pecans to cool completely at room temperature before slicing and serving. Enjoy!