UPDATE 10/26/09: Added printable recipe link at the bottom along with some backstory on the cake. Enjoy!
Fortunately, despite my cake-pan-size error, I was able to frost the cake without it going everywhere - the cake created a bit of a frame on the edges, which worked out great. I could have added some more sugar to the frosting, but I very much enjoyed licking the saucepan.
Let me tell you a story about this cake. My mother first had this cake at a party, and it was made by a woman named Mardi Glade. We always called this cake Mardi Glade when I was growing up, not Texas Cake, and I never heard the story behind it until I was an adult, about to bring the cake to a potluck, and I mentioned it to my mother, who quickly informed me that no one would have a clue what I made if I called it Mardi Glade cake. The cake went over just fine - better than fine, really, given that there was none to bring home, and once I told everyone that it was Texas Cake, I got knowing smiles and nods from the group. It's one of my favorite cakes, because it's super moist and yummy, but it's also ridiculously fast and easy to make. You can go from no cake to eating cake within usually about an hour. Pretty awesome, right? And warm Mardi Glade cake, woo, that's the best!
So, here is the recipe I made tonight - ATK's Texas Sheet Cake (slightly chocolate-y-ier than the original Mardi Glade cake) plus my mom's Mardi Glade frosting.
ATK Texas Sheet Cake
2 c all-purpose flour
2 c white sugar
1/2 tsp baking soda
1/2 tsp salt
1/4 c sour cream, room temperature
2 large eggs, room temperature
2 large egg yolks, room temperature
2 tsp vanilla extract
8 oz semisweet chocolate
3/4 c veg oil
3/4 c water
1/2 c cocoa powder (preferably Dutch-process)
4 T unsalted butter (1/2 stick)
1. Adjust an oven rack to the middle position and heat the oven to 350 degress. Grease an 18 x 13-inch rimmed baking sheet (I used a jelly roll pan, which is 15 1/2 x 11-inches). Whisk the flour, sugar, baking soda, and salt together in a medium bowl. In another medium bowl, whisk the sour cream, eggs, egg yolks, and vanilla together.
2. Melt the chocolate, oil, water, cocoa, and butter together in a large saucepan over medium heat, stirring occasionally, until smooth, about 5 minutes. Remove the saucepan from heat, and slowly whisk in the flour mixture until just incorporated (I did the opposite - poured the mixture from the saucepan into my medium bowl of flour mixture). Whisk in the egg mixture until just combined.
3. Give the batter a final stir with a rubber spatula to make sure it is thoroughly combined. Scrape the batter into the prepared baking sheet, smooth the top, and gently tap the sheet on the counter to settle the batter. Bake the cake until a toothpick inserted in the center comes out with a few moist crumbs attached, 18-20 minutes. (I think mine took about 25 minutes, all said and done.)
Mardi Glade Cake Frosting:
1/2 stick butter
3 Tbsp milk
5 Tbsp cocoa powder
1 tsp vanilla
2 1/4 c powdered sugar
Mix all ingredients well over low heat as cake finishes baking (last 4-5 minutes of baking). It will be lumpy, so don't bother trying to kill the lumps.
And here's the final product: