Easy Chocolate Number Cake (No Special Pans)

A chocolate number cake turns any birthday into something a little more special. You bake one big sheet pan of moist chocolate cake, cut out the numbers you need, and you never have to hunt down a shaped tin.

The cake itself is tender and deeply chocolatey. A simple vanilla buttercream sits between the layers and around the edges, ready to hold a pile of fresh berries or sprinkles.

Why This Cake Stays in the Rotation

It uses a basic sheet pan. You likely already own the only pan this recipe calls for, so there is no last-minute shop run for number-shaped moulds.

The cake stays soft for days. Oil and buttermilk in the batter mean it does not dry out after an afternoon on the counter, and the buttercream seals the cut edges.

Ingredients

• 1 3/4 cups all-purpose flour: spooned and levelled, never scooped straight from the bag
• 1 1/2 cups granulated sugar: adds structure and sweetness
• 3/4 cup unsweetened cocoa powder: Dutch-process or natural both work, just not hot chocolate mix
• 1 tsp baking powder
• 1 tsp baking soda
• 1/2 tsp fine sea salt
• 2 large eggs: at room temperature so they blend evenly
• 1 cup buttermilk: room temperature, shake the carton well before measuring
• 1/2 cup vegetable oil: or any neutral oil like canola
• 2 tsp vanilla extract
• 1/2 cup hot strong coffee: just-boiled water mixed with 1 tsp instant espresso powder, or use plain hot water if you prefer
• For the buttercream: 1 cup unsalted butter (softened), 3 cups icing sugar (sifted), 2 tbsp heavy cream or whole milk, 1 tsp vanilla extract, pinch of salt
• To decorate: fresh strawberries, raspberries, blueberries, macarons, or sprinkles, whatever you like

Variations / Substitutions

• Make it dairy-free: swap the buttermilk for 1 cup oat milk with 1 tbsp lemon juice, use a good vegan block butter for the frosting, and replace heavy cream with a splash of oat milk.
• Switch the filling: chocolate ganache, cream cheese frosting, or a stabilized whipped cream all work. Just make sure the filling is stiff enough to support the top cake layer.
• Skip the coffee: hot water with a pinch of extra salt still gives you a rich cake. The coffee does not add a coffee flavour, it just deepens the chocolate.
• Go mini: bake the batter in two 8-inch round pans and turn the cake into a stacked layer cake instead.

For a classic chocolate sheet cake that feeds a crowd, try my Best Chocolate Sheet Cake with Fudge Icing.

How To Make Chocolate Number Cake

Step 1: Mix the Chocolate Cake Batter

Preheat your oven to 350°F (180°C) and line a 9×13-inch metal baking pan with parchment paper, leaving a little overhang on the long sides. In a large bowl, whisk the 1 3/4 cups flour, 1 1/2 cups sugar, 3/4 cup cocoa powder, 1 tsp baking powder, 1 tsp baking soda, and 1/2 tsp salt until they are one uniform colour.

In a separate jug, whisk the 2 eggs, 1 cup buttermilk, 1/2 cup oil, and 2 tsp vanilla. Pour the wet mixture into the dry ingredients and stir with a rubber spatula until no streaks of flour remain, about 20 seconds. Add the 1/2 cup hot coffee and stir again; the batter will be very thin, and that is exactly what you want.

Step 2: Bake the Sheet Cake

Pour the batter into the prepared pan and gently tap it on the counter once to release any big air bubbles. Slide it into the centre of the oven and bake for 24 to 28 minutes.

The top will spring back when you press it lightly and a toothpick inserted in the middle will come out with a few moist crumbs clinging to it. Let the cake cool in the pan for 10 minutes, then use the parchment to lift it onto a wire rack and cool it completely. This takes about 2 hours, and the cake must be fully cool before you cut it or it will tear.

Step 3: Whip the Vanilla Buttercream

While the cake cools, place 1 cup softened unsalted butter in a big bowl. Beat it with an electric mixer on medium-high for 3 to 4 minutes, scraping the bowl once, until it is visibly paler and fluffy.

Turn the mixer to low and gradually add the 3 cups icing sugar, a little at a time, then pour in the 2 tbsp heavy cream, 1 tsp vanilla, and a pinch of salt. Once the sugar is incorporated, crank the speed to high and beat for 2 minutes more. The buttercream should be light, spreadable, and hold a soft peak.

Step 4: Cut Out the Number Shapes

Grab a sheet of printer paper and print your desired age in a large, bold font, or draw the number by hand so it fills most of an A4 page. Cut out the number to make a stencil.

Place the cooled cake slab on a large cutting board. Lay the paper number on top and trace around it gently with a toothpick. Lift the stencil, then trace the same shape a second time so you have two identical numbers. Use a long serrated knife and cut along the toothpick lines with a gentle sawing motion. Keep the offcuts for snacking.

Step 5: Pipe and Stack the Layers

Spoon about two-thirds of the buttercream into a piping bag fitted with a round tip, or just snip the end off a disposable bag so the opening is about 1/2 inch wide. Pipe little kisses or dots all over the surface of one cake number, covering it evenly from edge to edge.

Carefully set the second cake number directly on top, lining up the edges. Press down just enough so it settles, but not so hard that the buttercream squishes out the sides.

Step 6: Decorate and Serve

Switch to a small star tip or keep the same round tip and pipe swirls or dots around the perimeter of the top number. Fill the centre with whatever you like: halved strawberries, raspberries, a few macarons, a scatter of sprinkles.

Set the finished cake on a serving board, step back so everyone can admire it, then slice and serve. The cake cuts cleanest straight from the fridge, but the texture is softest at room temperature, so pull it out 20 minutes before you plan to eat.

Tips for the Best Number Cake

• Keep the cake cold before cutting. Pop the whole slab in the fridge for 30 minutes after it cools if your kitchen is warm. A firm cake cuts much cleaner.
• Use a sharp serrated knife for the numbers and wipe it between cuts. That stops the soft crumb from dragging.
• If your printed number looks too narrow, draw a slightly thicker version so there is enough cake to support the topping.
• Give the buttercream a quick beat again before piping if it has been sitting out more than an hour. It should be smooth and easy to squeeze.

Storing Leftover Number Cake

• Refrigerate: place leftover slices in an airtight container and keep chilled for up to 4 days. The cake will stay moist and the buttercream holds its shape.
• Serve cold: Cold slices straight from the fridge are nice when the frosting is firm and the cake is dense. Let it sit 15 to 20 minutes if you prefer a softer bite.

Frequently Asked Questions

Can I make the cake layers ahead of time?

Yes. Bake the sheet cake, cool it completely, wrap the whole slab tightly in plastic wrap, and freeze it for up to a month. Thaw it in the fridge overnight before cutting the numbers.

What if I do not have buttermilk?

Combine 1 cup whole milk with 1 tablespoon lemon juice or white vinegar, stir, and let it sit for 5 minutes. It will thicken a little and work perfectly.

Can I use a different filling instead of buttercream?

Absolutely. A stiff chocolate ganache, cream cheese frosting, or even a thick pastry cream all work. Just make sure the filling is firm enough to hold the top layer without sliding.

How do I move the cut-out numbers without breaking them?

Slide a large offset spatula or a flat cake lifter under the whole number. Using two spatulas helps keep it steady. A chilled cake lifts more easily than a warm one.

Chocolate Number Cake Recipe

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 25 minutes mins

Total Time 55 minutes mins

Servings: 12 servings

Calories: 480

Ingredients Method Notes

Ingredients

  

• 1 3/4 cups all-purpose flour
• 1 1/2 cups granulated sugar
• 3/4 cup unsweetened cocoa powder
• 1 tsp baking powder
• 1 tsp baking soda
• 1/2 tsp fine sea salt
• 2 large eggs
• 1 cup buttermilk
• 1/2 cup vegetable oil
• 2 tsp vanilla extract
• 1/2 cup hot strong coffee
• 1 cup unsalted butter, softened
• 3 cups icing sugar, sifted
• 2 tbsp heavy cream or whole milk
• 1 tsp vanilla extract (for buttercream)
• Pinch of salt
• Fresh berries, macarons, or sprinkles for decorating

Method

 

1. Preheat oven to 350°F (180°C). Line a 9×13-inch pan with parchment. Whisk flour, sugar, cocoa, baking powder, baking soda, and salt in a large bowl.
2. In a jug, whisk eggs, buttermilk, oil, and 2 tsp vanilla. Stir into dry ingredients until combined, then mix in hot coffee. The batter will be thin.
3. Pour batter into the pan, tap once, and bake 24 to 28 minutes until a toothpick has moist crumbs. Cool in pan 10 minutes, then lift onto a wire rack and cool completely.
4. Beat butter on medium-high until pale and fluffy, about 3 to 4 minutes. Gradually add icing sugar, then 2 tbsp cream, 1 tsp vanilla, and salt. Beat on high 2 minutes until light.
5. Print and cut out a large paper number. Place on the cooled cake, trace with a toothpick twice, and cut out both numbers with a serrated knife.
6. Pipe buttercream dots over one cake number, place the second number on top, then pipe swirls around the edge. Fill the centre with berries or decorations and serve.

Notes

Cool the cake fully before cutting, about 2 hours. For the cleanest slices, chill the assembled cake 20 minutes before serving. The coffee can be replaced with hot water; it does not add coffee flavour, only depth.