Vanilla Texas Sheet Cake with Buttermilk and Cooked Icing
This vanilla Texas sheet cake feeds a crowd with almost no fuss, the kind of dessert you write on a recipe card because someone will ask for it every time. A vanilla buttermilk cake bakes thin and tender in a sheet pan, then a warm cooked icing goes right over the top and sets into a soft, slightly crackly surface.
That thin layer of icing melts into the hot cake just a little, so every bite stays moist without turning heavy. It is the cake to bring to a potluck, a bake sale, or a birthday where you need a lot of dessert that does not eat up your whole afternoon.
What Makes This Vanilla Sheet Cake So Good
A hot butter and water mixture gets poured straight into the dry ingredients, which sounds odd but gives the cake a fine, even crumb that stays soft for days. The buttermilk adds a gentle tang you notice mostly as extra tenderness, not a strong sour note.
The icing is just butter, milk, and powdered sugar cooked on the stove. You pour it over the cake while both are still warm, and as it cools it gets that fudge-like surface that cracks under a fork. No whipping, no layering, no waiting around.
Ingredients
- 2 cups all-purpose flour: spoon and level, do not shake the cup.
- 2 cups granulated sugar
- 1 tsp baking soda
- 1/2 tsp fine salt
- 1 cup unsalted butter
- 1 cup water
- 1/2 cup buttermilk: full-fat best, but low-fat works.
- 2 large eggs: at room temperature if you remember.
- 2 tsp vanilla extract: the real stuff if you have it.
- 6 tbsp unsalted butter: for the icing.
- 6 tbsp whole milk
- 4 cups powdered sugar: sift if it is lumpy.
- 1 tsp vanilla extract
- Pinch of salt
Variations / Substitutions
- Almond or lemon extract: Swap half the vanilla in the cake and icing for 1 tsp almond extract, or 1 tsp lemon extract with a little zest in the batter for a bright citrus sheet cake.
- Browned butter icing: Brown the 6 tbsp butter for the icing before adding the milk, then carry on. It gives a nutty depth that works well against the sweet vanilla.
- No buttermilk: Combine 1/2 cup milk with 1 1/2 tsp white vinegar or lemon juice, stir, and let it sit 5 minutes. It will not be quite the same but your cake will still be tender.
- Dairy-free: Use a good plant-based butter and unsweetened oat milk in both cake and icing, and swap buttermilk for oat milk soured with a little vinegar.
- Half-sheet cake: Double the recipe, bake in an 18×26-inch pan, and increase the icing by half again. Watch the bake time, it may need an extra 3 to 5 minutes.
If you want the chocolate version, try Chocolate Texas Sheet Cake next.
How to Make Vanilla Texas Sheet Cake
Step 1: Mix the Batter
Whisk the flour, sugar, baking soda, and salt together in a large bowl. In a medium saucepan, combine the 1 cup butter and 1 cup water and set it over medium heat. Bring it to a boil, which takes about 4 minutes, then immediately pour the hot liquid over the dry mixture. Stir with a wooden spoon until no dry streaks remain.
The batter will be thin and bubbly from the heat, more like a crepe batter than a thick cake batter. That is what you want.
Step 2: Bake the Cake
While the oven preheats to 400°F (200°C), grease a 13×18-inch sheet pan with butter or nonstick spray. Whisk the buttermilk, eggs, and 2 tsp vanilla into the batter until completely smooth and pourable. Pour the batter into the prepared pan and tilt the pan to level it out. Bake for 15 to 18 minutes, until a toothpick poked in the center comes out clean or with a few moist crumbs.
The top will be golden and spring back lightly when you press it. The edges may pull away from the sides a hair. Start checking a minute or two early if your oven runs hot.
Step 3: Cook the Icing
While the cake bakes, make the icing. Combine the 6 tbsp butter and 6 tbsp milk in a clean saucepan and set it over medium heat. Cook, stirring often, just until the butter melts and the mixture comes to a simmer, about 2 minutes. Remove the pan from the heat and whisk in the powdered sugar, 1 tsp vanilla, and a pinch of salt until the icing is glossy and smooth.
The icing will be pale and slightly thick, but pourable. If it sits too long it will begin to set, so have it ready right when the cake comes out of the oven.
Step 4: Ice and Serve the Cake
As soon as the cake is out of the oven, pour the warm icing all over the top. Use an offset spatula or the back of a spoon to spread it to the edges quickly, while the icing is still fluid. Let the cake cool on a wire rack for at least 20 minutes so the icing can firm up.
Slice into squares while still slightly warm. The icing will have a soft, fudge-like layer on top and each piece lifts out cleanly with a moist crumb underneath. Serve the squares on a big platter or right from the pan, the way a sheet cake is meant to go.
Tips for the Best Vanilla Sheet Cake
- Measure the flour by spooning it into the cup and leveling it off. Scooping straight from the bag packs in too much and makes a heavy crumb.
- Use real buttermilk if you can. Its thickness and acidity give the cake a structure that does not dry out, even after a day on the counter.
- Pour the icing while the cake is still piping hot from the oven. That heat pulls the icing slightly down into the surface so it binds instead of just sitting on top.
- If your powdered sugar is old or clumpy, sift it first or the icing may have lumps that never smooth out.
- A metal sheet pan works best for even browning. If you use a glass pan the cake may need an extra 2 to 3 minutes in the oven.
Bake times adjust by pan size:
| Pan Size | Bake Time | Icing Adjustment |
|---|---|---|
| 13×18 inches | 15 to 18 mins | Full recipe |
| 10×15 inches | 18 to 22 mins | Reduce icing by 1/4 |
| 9×13 inches | 22 to 26 mins | Halve the icing |
Storing Leftovers
- Refrigerate: Keep covered at room temperature for up to 2 days, or refrigerate in a sealed container for up to 4 days. The icing may soften in the fridge but the cake stays moist.
- Reheating: A single slice warms up nicely in the microwave for 10 to 15 seconds, which brings back that just-baked softness. No need to reheat the whole pan.
- Serve cold: Straight from the fridge the icing gets firmer, almost like a thin fudge layer. Some people prefer it that way.
Frequently Asked Questions
Can I make this cake the night before?
Yes. Bake it, ice it, cool completely, then cover and leave it on the counter overnight. The crumb will still be moist the next day.
Why did my icing turn out grainy?
If the butter and milk were not hot enough when you whisked in the powdered sugar, the sugar may not have dissolved fully. Make sure the liquid reaches a simmer before adding the sugar.
Can I freeze the cake?
Yes, cut it into squares and freeze them in a single layer on a pan, then transfer to a zip-top bag once solid. Thaw at room temperature for about an hour.
Can I use something other than buttermilk?
You can sour regular milk with a little vinegar or lemon juice as noted above, but the cake will not be quite as tender. Yogurt thinned with a little milk also works, use 1/2 cup thinned yogurt.
The icing set before I could pour it. What now?
Return the pan to the stove over low heat and stir constantly just until it loosens, about 30 seconds. It will become pourable again, so work quickly.
Vanilla Texas Sheet Cake Recipe
Ingredients
Method
- Whisk flour, sugar, baking soda, and salt in a large bowl. Combine 1 cup butter and 1 cup water in a saucepan, bring to a boil over medium heat, then pour over dry ingredients and stir.
- Preheat oven to 400°F (200°C) and grease a 13×18-inch sheet pan. Whisk buttermilk, eggs, and 2 tsp vanilla into batter. Pour into pan and bake 15 to 18 minutes.
- While cake bakes, melt 6 tbsp butter and 6 tbsp milk in a saucepan over medium heat until simmering. Remove from heat, whisk in powdered sugar, 1 tsp vanilla, and a pinch of salt until smooth.
- Pour warm icing over hot cake, spread quickly, and let cool at least 20 minutes before slicing.
