Chocolate Sheet Cake (Texas)

Texas sheet cake is an American dessert made with a combination of buttermilk, eggs, vanilla, baking soda, sugar, flour, butter, and cocoa. Once baked, the hot chocolate cake is topped with a crunchy icing featuring pecan pieces. In Texas, it is a staple at funerals, but it is also often seen in churches. The cake is beloved because it is easy to prepare and has a moist and gooey texture. Although its place of origin is still unknown, most people agree that it was invented in Texas due to the usage of local ingredients such as buttermilk and pecans.

Cake:
2 sticks unsalted butter, room temperature, for pan
2 cups all-purpose flour, unbleached
2 cups granulated sugar
1 tsp. baking soda
1 tsp. coarse salt
½ tsp. ground cinnamon
¼ cup unsweetened natural cocoa powder
2 large eggs, lightly beaten
½ cup buttermilk
1 tsp. pure vanilla extract

Icing:
6 Tbsp. unsalted butter
3 Tbsp. unsweetened natural cocoa powder
6 Tbsp. heavy cream
1½ tsp. pure vanilla extract
1¾ cups + 2 Tbsp. confectioners' sugar, sifted
1 cup (4 oz) toasted pecans, finely chopped

For the Cake:
Preheat oven to 375°F (190°C/170°C fan, Gas Mark 5). Lightly butter a 9x13" cake pan. Line with parchment, leaving a 2" overhang on long sides.

In a large heatproof bowl, whisk together flour, granulated sugar, baking soda, salt, and cinnamon.

Melt butter in a saucepan over medium-low. Whisk in cocoa, then 1 cup water. Increase heat to medium-high and bring to a boil, whisking occasionally. Pour over flour mixture and stir to combine. Stir in eggs, buttermilk, and vanilla.

Pour batter into prepared pan; smooth top with an offset spatula. Bake until a tester inserted in center comes out clean, 22-24 minutes.

Icing: In a small saucepan, bring butter, cocoa, and cream to a boil, stirring occasionally. Remove from heat; whisk in vanilla and confectioners' sugar. Let stand until warm before using.

Transfer cake in pan to a wire rack; let cool 15 minutes. Pour glaze over cake. (For a more elegant presentation, remove cake from pan using parchment and place on a serving platter before glazing.) Sprinkle with pecans and let cool before serving.