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School dinner cake sliced into squares

Gluten Free Old School Sponge Cake

Gluten free old School Dinner Cake. So easy and delicious. The perfect old school sprinkle tray bake is a fun party cake that everyone will love and no one will know it's gluten-free!
5 from 9 votes
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Course: Dessert
Cuisine: British
Keyword: gluten free, School Dinner Cake, sponge cake, sprinkle tray bake
Prep Time: 10 minutes
Cook Time: 40 minutes
Servings: 18 slices
Author: Amanda


  • large baking tin I used 13"x10"


Sponge Cake

  • 450 grams Gluten free Self Raising Flour  To make self raising flour at home by mixing 2 teaspoons of baking powder with every 125 grams of Gluten free All purpose flour (Plain flour in the UK).
  • 450 grams Marg/Butter (Room temperature) To make Dairy free use Dairy free spread of your preference
  • 400 grams Caster Sugar
  • 7 Eggs (Room temperature)
  • 2 teaspoon Baking Powder
  • 2 teaspoon Vanilla extract
  • ½ teaspoon Xanthan Gum


  • 300 grams Icing Sugar Powdered sugar
  • 4-5 tablespoons Water
  • Sprinkles of choice
  • few drops Food Colouring (optional)



  • Preheat oven to 170°C/325°F/Gas mark 3
  • Prepare baking tin with grease proof paper. I prefer to fold paper over the sides of the tin as this makes it easier to lift the cake from the tin when cooled.
  • In a large bowl mix all the sponge ingredients together until it forms a smooth consistency.
  • Pour the mixture into prepared baking tin and spread out evenly.
  • Bake in the Oven for approximately 40 mins insert a skewer into cake after this time if it comes out clean its ready if not leave it in a slightly longer. (Times may vary slightly dependant on oven). Transfer tin to cooling rack and leave to cool.


  • Sieve icing sugar into medium size bowl. Add 1tsp of water at a time and mix until you get desired consistency.
  • Add food colouring if desired.
  • Spread Icing over cake evenly and then drop over desired sprinkled (I like to use brightly coloured sprinkles for that Retro look).


NOTE: Always check that all your ingredients are gluten free. Some Sprinkles do contain gluten so always read the labels.
STORAGE: This can be stored in an airtight container for you to enjoy for up to 5 days.
SERVING SUGGESTION: Service with hot custard for that true nostalgic feeling.
FREEZING: The sponge can be frozen in a freezer safe container for up to 3 months. Then add icing once defrosted.