Old Fashioned Texas Sheet Cake from Scratch

Old fashioned Texas sheet cake is a thin, tender chocolate cake baked in a large rimmed pan and covered with warm cocoa frosting while the cake is still hot. This regional American favorite gets its rich flavor from cocoa and butter, while boiling water blooms the cocoa and helps keep the crumb moist; versions vary, especially in whether they include nuts.

Ingredients

2 cups (250 g) all-purpose flour, spooned into the measuring cup and leveled
2 cups (400 g) granulated sugar
1 teaspoon baking soda
1/2 teaspoon fine salt
1 cup (227 g) unsalted butter, cut into pieces, plus extra for greasing
1/4 cup (21 g) unsweetened natural cocoa powder
1 cup (240 ml) water
1/2 cup (120 ml) buttermilk, at room temperature
2 large eggs (about 100 g without shells), at room temperature
1 teaspoon vanilla extract

For the frosting:

1/2 cup (113 g) unsalted butter, cut into pieces
1/4 cup (21 g) unsweetened natural cocoa powder
6 tablespoons (90 ml) milk
3 1/2 cups (420 g) powdered sugar, sifted if lumpy
1 teaspoon vanilla extract
1/2 cup (60 g) chopped pecans or walnuts, optional

Instructions

Heat the oven to 350°F (175°C). Grease a 13-by-18-inch (33-by-46-cm) rimmed half-sheet pan with butter. Make sure the pan has a rim at least 1 inch (2.5 cm) high; the batter is thin and the frosting is poured over the cake.
In a large bowl, whisk together the flour, sugar, baking soda, and salt. In a medium saucepan, combine the 1 cup (227 g) butter, cocoa, and water. Heat over medium heat, stirring, until the butter has melted and the mixture just reaches a boil. Remove it from the heat.
Pour the hot cocoa mixture over the flour mixture and whisk until smooth, scraping the bottom and sides of the bowl. In a separate bowl, whisk the buttermilk, eggs, and 1 teaspoon vanilla. Gradually whisk this into the batter until evenly combined. The batter will be loose; that is normal.
Pour the batter into the prepared pan and spread it evenly into the corners. Bake for 18–22 minutes, until the center springs back lightly when touched and a toothpick inserted in the middle comes out with a few moist crumbs, not wet batter. Begin checking at 18 minutes; a thin cake can overbake quickly.
During the last few minutes of baking, make the frosting. In a saucepan, combine the frosting butter, cocoa, and milk. Warm over medium heat, stirring until the butter melts and the mixture is smooth; do not let it boil vigorously. Remove from the heat and whisk in the powdered sugar a cup at a time, followed by the vanilla. Stir in the nuts if using. If the frosting becomes too thick to pour, whisk in milk 1 teaspoon (5 ml) at a time.
As soon as the cake comes out of the oven, pour the warm frosting over it. Gently spread it with an offset spatula so it reaches the edges. Let the cake cool in the pan until the frosting sets, about 20 minutes, before slicing. The frosting firms but remains soft enough to cut cleanly with a sharp knife.

Tips

Measure flour lightly. Spoon it into the cup and level it rather than packing it down; too much flour makes this thin cake dry and dense. A kitchen scale gives the most consistent result.
Use a rimmed pan of the right size. A smaller pan makes the batter deeper and changes the baking time. If you only have a 13-by-9-inch (33-by-23-cm) pan, do not pour all the batter into it; use a larger oven-safe pan or bake in batches rather than risk overflow.
Frost while hot. Pouring the frosting onto the just-baked cake lets it settle into a smooth layer. Waiting until the cake is cool can make the frosting harder to spread and less glossy.
Buttermilk substitute: Stir 1 1/2 teaspoons lemon juice or white vinegar into 1/2 cup (120 ml) milk and let it stand for 5 minutes. It provides acidity, though the cake may be slightly less rich than with real buttermilk.

Serving Suggestions

Serve the cake at room temperature, cut into small squares; its cocoa frosting makes each piece quite rich. Add a scoop of vanilla ice cream or a spoonful of lightly sweetened whipped cream for a dessert plate. For a simpler serving, pair it with coffee or a glass of cold milk. Since the cake is baked in its serving pan, it also travels easily to a potluck once completely cool and covered.

Variations

For the familiar nut-topped version, use pecans in the frosting; walnuts work too, or leave the nuts out for a smooth finish. A pinch of cinnamon in the batter adds a gentle warmth without changing the method. For deeper chocolate flavor, use a good-quality natural unsweetened cocoa; Dutch-process cocoa is less acidic and can alter how the baking soda works, so natural cocoa is the reliable choice here. You can also add 1/2 teaspoon instant espresso powder to the cocoa mixture, which emphasizes the chocolate flavor without making the cake taste strongly of coffee.

Storage and Reheating

Keep the cake covered at room temperature for up to 2 days if your kitchen is cool, or refrigerate it for 3–4 days. Refrigerate within 2 hours of baking, particularly in a warm room. Bring chilled portions to room temperature for about 20–30 minutes before serving for a softer crumb and frosting. To warm an individual piece, microwave it for 8–12 seconds, then check and add a few seconds if needed; avoid overheating, which can make the cake dry and the frosting runny. For longer storage, freeze individual pieces, well wrapped, for up to 2 months; thaw overnight in the refrigerator or at room temperature until soft.

Frequently Asked Questions

What pan is best for Texas sheet cake?
A 13-by-18-inch rimmed half-sheet pan produces the traditional thin cake and gives the warm frosting room to spread. A pan with a rim is essential; a flat cookie sheet will not safely hold the batter.

Can I make the cake ahead?
Yes. Bake and frost it a day ahead, let the frosting set, then cover the pan. For the best texture, store it in a cool room for up to 2 days or refrigerate it and allow time for it to warm slightly before serving.

Why is my cake dry?
Common causes are measuring too much flour, baking too long, or using a pan that is too small and requires a longer bake. Check the center near the start of the timing range and remove the cake when a toothpick shows a few moist crumbs.

Can I use salted butter?
Yes. Use the same amount and reduce the added salt to a small pinch, or omit it. Salt levels vary among brands, so the flavor may be a little different.

Does Texas sheet cake need to be refrigerated?
It can stay covered at cool room temperature for up to 2 days, but refrigerate it within 2 hours if the room is warm or if you need to keep it longer. Refrigerated cake keeps for 3–4 days.

Can I leave out the nuts?
Yes. The pecans or walnuts are optional and can be omitted without changing the cake or frosting method. For a nut-free gathering, check ingredient labels and prevent contact with other foods containing nuts.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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