Instructions:

1. Adjust oven rack to middle position and preheat oven to 350ºF.
2. Grease one 18" x 13" rimmed baking sheet.
3. In a medium-sized bowl mix:
• 2 cup all-purpose flour
• 2 cup granulated sugar
• ¹/₂ tsp baking soda
• ¹/₂ tsp salt
4. In a separate bowl whisk together:
• 2 eggs, large
• 2 egg yolks
• 2 tsp vanilla extract
• ¹/₄ cup sour cream
5. In a double boiler, melt on medium heat until smooth, 3-5 minutes:
• 8 oz chocolate chips, semi-sweet , chopped
• 4 TBS butter, unsalted
• ³/₄ cup vegetable oil
• ³/₄ cup water
• ¹/₂ cup cocoa powder, unsweetened
6. Whisk chocolate mixture into flour mixture until incorporated.
7. Whisk egg mixture into batter.
8. Pour batter into prepared baking sheet.
9. Bake until tooth pick inserted in center comes out, 18-20 minutes.
10. Transfer to a cooling rack.
11. About 5 minutes before cake is done, heat in a small saucepan over medium heat, stirring occasionally until smooth:
• 8 TBS butter, unsalted
• ¹/₂ cup heavy cream
• ¹/₂ cup cocoa powder, unsweetened
• 1 TBS corn syrup, light
12. Turn heat off and stir in until smooth:
• 3 cup powdered sugar
• 1 TBS vanilla extract
13. Spread warm icing evenly over hot cake.
14. Sprinkle with:
• 1 cup pecans , toasted & chopped
15. Let cake cool to room temperature on a cooling rack, about 1 hour.
16. Refrigerate until icing is set, about 1 hour.
17. Cake can be wrapped in plastic and refrigerated for up to 2 days.
18. Bring to room temperature before serving.
19. Cut into 3" squares and serve.