Easy Sprinkle Cake Tray Bake with Buttercream Icing
A nostalgic sheet cake that brings back school dinner memories with its simple, foolproof sponge and bright sprinkle topping. This crowd-pleasing tray bake uses the creaming method to combine butter and sugar into a light crumb that stays moist for days. The contrast between soft vanilla sponge, smooth icing, and crunchy sprinkles delivers the comfort and joy of a classic British school cake. Ideal for bakers of any skill level, especially those introducing children to cake-making, it's perfect for lunchboxes, potlucks, or afternoon tea. What sets this version apart is its flexibility—bake as one tray, cupcakes, or individual portions—and the forgiving nature of the recipe, which works with pantry staples. The optional custard serving enhances it to a proper dessert experience rather than just a sweet treat.
Ingredients
- 1 ¼ cups sugar
- 18 tbsp softened butter
- 2 cups self-rising flourplain flour mixed with 2 tsp baking powder1:1baking
use measured baking powder for accuracy
- 4 eggs
- 1 tablespoon milk(optional)
- 1 teaspoon vanilla essencevanilla extract0.75:1baking
extract is stronger; reduce slightly
- 1 ½ cups powdered sugar
- sprinkles
- custard(optional)
Instructions
- 1
Preheat the oven to 350°F or 325°F fan.
- 2
Cream together the softened butter and sugar until smooth.
- 3
Mix in the eggs one at a time, beating well after each addition.
- 4
Stir in the flour gradually to create a smooth batter.
- 5
Stir in the milk and vanilla essence.
- 6
Transfer to a lined or greased baking tray.
- 7
Bake for around 25-30 minutes until golden and a skewer comes out clean.
- 8
Allow the cake to cool fully.
- 9
For the icing, combine the powdered sugar with warm water a tablespoon at a time until you have a thick but runny paste.
- 10
Spread the icing over the cooled cake.
- 11
Top with sprinkles and allow icing to set before cutting.
Tips
If using plain flour instead of self-raising, add two teaspoons of baking powder mixed thoroughly with the flour before adding to the wet ingredients. This ensures even distribution and consistent rise.
For the icing, start with less water than you think you need. Add it gradually until you reach the right consistency—thick but still spreadable. Using warm water helps dissolve the icing sugar faster and creates a smoother paste.
Bring all ingredients, especially butter and eggs, to room temperature before mixing. This creates a smoother batter and helps the cake rise evenly, preventing a dense crumb.
Good to Know
Keep covered at room temperature for up to 3 days. Store in an airtight container to maintain moisture and prevent the icing from drying out.
Bake the sponge up to 2 days ahead; wrap uniced in plastic wrap. Make the icing and assemble no more than 4 hours before serving to keep sprinkles vibrant and icing set.
Serve at room temperature with custard poured over warm cake, or with cold custard on the side. Also excellent with a glass of cold milk or tea.
Common Mistakes
Add flour all at once to avoid overmixing, which toughens the crumb and reduces rise.
Use room-temperature eggs and butter to prevent curdling, which creates a dense, heavy cake.
Don't skip cooling the cake fully before icing, or the icing will melt and slide off.
Substitutions
Dairy-Free Swaps
General Alternatives
use measured baking powder for accuracy
FAQ
Can I bake this as cupcakes instead?
Yes. Divide the batter among cupcake cases and bake for 18-20 minutes instead. The recipe makes approximately 12 cupcakes. Check doneness with a skewer as you would the tray bake.
Can I make this without self-raising flour?
Yes. Mix two teaspoons of baking powder thoroughly with 250g plain flour before adding to the wet ingredients. Sift if possible to avoid lumps. This substitution works with no change to the method.
How long does the finished cake keep?
Covered at room temperature, the cake stays fresh for up to 3 days. The sponge dries out slightly after day 2, but icing helps seal in moisture. Refrigerate if storing longer than 2 days.