When the knife goes through a frog cake, it cuts the glossy green skin first. Then it passes through a firm, pale dome of cream and reaches two layers of soft sponge with a thin red line of jam between them. Two eyes sit on top, and a little smile is pressed under them. These small square cakes come from Adelaide, the capital of South Australia. They are very sweet: butter and sugar on every side, with only the jam to cut through it. One cake is rich enough to share in quarters at teatime.
From Adelaide's tea rooms to a state icon
The frog cake belongs to Balfours, an Adelaide bakery that goes back to 1853. That year, the Scottish immigrants James Calder and Margaret Calder (born Balfour) opened their first shop on Rundle Street. In 1894 Elizabeth Balfour opened a café and confectionery on the same street. In 1924 the firm became Balfour Wauchope. The frog cake arrived in the early 1920s, when tea rooms were thriving and the city liked small, pretty cakes with its tea. The idea came from French pâtisserie, where fondant-covered petits fours were already being made.
A year nobody can pin down
Where the frog cake began is not settled. One account names 1922 and credits Gordon Balfour after a trip to France. Gordon did not travel to Europe until 1928, though, and in 1922 he was still a pupil at Prince Alfred College. Another account points to his father, Jack Balfour, and a trip to Paris in 1923. The bakery's history says only that the frog cake existed by the 1920s. In 2023 Adelaide marked the frog cake's hundredth year, with celebrations planned and talk of a statue in Rundle Mall. The cake has a look in common with the Swedish princess cake, but that recipe appeared in print in the 1930s, so it was unlikely to be the model.
Green first, then pink, brown and team colours
The first frog was green. Pink and brown (chocolate) frogs came later, and the bakery has also made red frogs for Christmas, Santas, snowmen, Easter chicks and frogs in the colours of the Adelaide Football Club. One writer who grew up in Adelaide remembers the frog cake as the treat on a day spent shopping in town. The frog is counted as a South Australian heritage icon, a status dated to 2001. The same year, after many copies, Balfours trademarked the name and the shape. What you make at home here is a home version for your own table, built in the same layers.
For most of its life the frog cake was sold only inside South Australia. Attempts to sell it across the country never really worked, partly because the cakes travel badly: in summer heat, a box that tips over arrives with the icing melted. The bakery passed to San Remo in 2008 and to Aus Pie Co of Western Australia in 2023. For more of the country's cooking, see our Australia page.
Denmark has its own frog cake, frøkage, from the 1950s. In the 1970s it took the name kajkage after Kaj, the frog in the puppet show "Kaj & Andrea". It sits on a thin macaroon base under green marzipan. Mr Kipling's French Fancies in Britain look similar but are a different product. Australia also has a whole party cake called a frog cake, baked from mix in a big tray and cut into the shape of a frog. This article is about the small, single Adelaide cake.
Ingredients
This makes one 8-inch (20 cm) square pan of sponge, cut into 1½-inch (4 cm) squares. The butter is listed twice: one portion for the sponge, one for the buttercream. Keep them apart and do not move butter from one to the other.
Frog cakes contain wheat, egg and milk. Check the labels on the jam, the fondant and both icings, because their ingredients vary by product. Use food colouring within the amount on its label.
Equipment
- 8-inch (20 cm) square cake pan, at least 1½ inches (4 cm) deep
- Parchment paper
- Electric mixer and two mixing bowls
- Wooden skewer
- Wire rack
- Long serrated knife or cake leveller
- Offset palette knife and a small palette knife
- Piping bag with a ⅜-inch (1 cm) plain round nozzle
- Rolling pin, with ¼-inch (6 mm) guides or a ruler
- Small sharp knife
- Small round cutter, for pressing the mouth
- Small fine-tipped piping bags or tubes for the white and black icing
- Paper cases
- Oven thermometer
Choosing and substituting
Ready-to-roll icing decides the look. This is the firm cake fondant, sometimes sold as sugar paste, that rolls out and drapes over a cake. Look for it at cake-decorating shops or online, and a block that is already green saves colouring work. A quick paste of icing sugar and water will not roll to ¼ inch (6 mm) or drape over the dome. If you have to use one, treat it as a spread-on glaze finish, and expect a different cake.
Buy self-raising flour from an import grocer or online if your supermarket does not stock it. You can swap in plain flour and baking powder, but the total leavening changes, and so does the rise of the sponge. For colouring, a gel adds green without adding water. Liquid colouring softens the fondant and makes it harder to drape.
The rest is easy to find. Caster sugar can be replaced with ordinary granulated sugar. Any strawberry jam works, and one with some fruit or seeds gives a clearer stripe.
The frog cake reads as itself when it has a square body, a domed head and a rolled fondant skin. Colour and jam are free choices. A round pan or a poured glaze moves it toward a different cake.
Method
Baking is the quick part. The work is the assembly. Mix and bake the sponge first, then let it cool completely in the pan. That cooling time is when you can soften the second portion of butter for the buttercream. The domes then need 30 minutes in the refrigerator, which is the moment to clear the board for rolling fondant. After that, the coating and the faces go one cake at a time.
When it goes wrong
| What you see | Why | What to do |
|---|---|---|
| The sponge is tough or coarse | The butter was cold, or the batter was overmixed | Next time, soften the butter fully and stop beating as soon as the batter is smooth and glossy |
| The sponge barely rose | The leavening was stale, or plain flour replaced self-raising flour | Use fresh self-raising flour and baking powder |
| The layers slide when cut | Too much jam, or the knife was sawed | Spread the jam thinner and press straight down |
| The domes slump | The buttercream was soft, or the chill was cut short | Keep the full icing sugar and give the domes the full 30 minutes in the refrigerator |
| Crumbs show under the fondant | The sides were not crumb-coated | Coat every side thinly before the fondant goes on |
| Fondant tears or wrinkles | It was rolled too thin, or the corners were rounded | Roll to ¼ inch (6 mm) and keep the crumb coat thin so the corners stay sharp |
| The fondant looks wet and the colour bleeds | Condensation after the cold refrigerator | Do not wipe it; take the cakes out only a short time before serving and serve promptly |
Serving, variations and storage
At the table
Frog cakes belong at teatime with a pot of black tea. They are rich enough to cut into quarters, so set out a small knife and let people share one. For a birthday or a school treat, line the frogs up in their paper cases on a plain plate and let the colours stand out. Serve them chilled or after a short rest at room temperature. Never warm them, because the fondant melts.
Variations
- Pink or brown frogs. Colour the fondant pink or brown instead of green, the way Adelaide's frogs come in three colours. The taste stays the same, and a mixed plate looks like a bakery tray.
- Another jam. Use the same weight of a different jam. A sharper jam makes the cake taste less sweet.
- The open mouth. Cut the mouth with a hot knife so the buttercream shows. The face looks closer to the frog sold in Adelaide.
- Seasonal colours. Make red frogs for Christmas or Easter chicks, or use your team's colours. Change only the fondant colour and keep the recipe as written.
Storage
Keep the frogs covered with wrap or in an airtight container in the refrigerator, and bring them out only a short time before eating. Do not leave them at room temperature for long: the buttercream is a dairy filling, and the fondant sweats as it warms.
Frequently asked questions
Can I bake the sponge in a round pan?
Use the 8-inch (20 cm) square pan. A round pan changes how the cake cuts into 1½-inch (4 cm) squares and leaves more curved offcuts. The square edges are also what give the frog its straight body.
What is mock cream, and should I use it?
Mock cream is the lighter cream inside the frog cakes Adelaide's bakery sells. Buttercream is the usual choice at home because it pipes into a firm dome that holds up under ¼-inch (6 mm) fondant. The cake tastes richer with buttercream, so the small portions matter more.
Can I take frog cakes to a picnic or post them?
They travel poorly. Heat softens the buttercream and melts the fondant, and a box that tips over spoils the faces. Carry them cold, in a container where they cannot slide, and eat them soon after you arrive.
Should the fondant feel hard once it sets?
It firms up on the outside but stays soft enough to take a fingerprint. Handle the cakes by their paper cases, not by the fondant.
