Microwave mug cakes put to the (taste) test

Natasha Rudra
Jelly-like: the Chocolate fondant mug cake was a good hit.
Jelly-like: the Chocolate fondant mug cake was a good hit. Photo: Jamila Toderas

If you work in an office, the chances are that you've seen a forwarded email or a Facebook post with a recipe for a chocolate cake that you can make in your tea room with just a couple of spoonfuls of simple ingredients in your coffee mug. Pop it into the office microwave and voila – a tiny cake just for you, at work. Morning tea anytime you want. So when a little book came across the Food & Wine desk that had a whole collection of recipes for these little workplace-friendly baked goods it seemed like a sign. 

Mug Cakes by Lene Knudsen promises "soft melting cakes ready in 5 minutes". There are luscious photographs of mini cakes in coffee cups and mugs. They come in a variety of really quite fancy flavours: a white chocolate financier, a green tea cake with raspberries, a chocolate fondant topped with berries and meringue. There's a whole section of cookie recipes which you bake in the bottom of your mug and eat with a spoon. The book even includes a collection of sauces that you can make in the microwave to top your little cake. 

Whopping: Making the marshmallow and peanut butter mug cake was strangely exhausting.
Whopping: Making the marshmallow and peanut butter mug cake was strangely exhausting. Photo: Jamila Toderas

How can anyone resist? I certainly can't. Neither could my coworkers. Every time I had the book out in the pile on my desk, someone would walk past, take a look at the mug cakes, and suggest that I road test the recipes. So I picked out a couple of recipes, roped in photographer Jamila Toderas and headed to the Fairfax Media Canberra Test Kitchen. Sorry, the tea room. 

Marshmallow mug cake

The first recipe looks intriguing: a peanut butter-flavoured cake topped with marshmallows. But the first hurdle turns out to be measuring butter. The recipe calls for a "slice of butter" about 3/4 centimetres thick or about 15 grams. My slicing is imprecise. Never mind. We grab a mug and beat in an egg, a tablespoon and a half of sugar, cream, a whopping three tablespoons of peanut butter, baking powder and melted butter. Five tablespoons of flour need to be beaten in – a strangely exhausting task when you're trying to beat a very stiff batter in the confines of a coffee mug. It's like trying to have a wrestling match in a shoebox. "It's really hard," I gasp after a minute or two. Jamila looks at me sceptically. I make a mental note to work on my upper body strength. 

A single marshmallow, cut into quarters, goes on top of the batter (it's practically a dough) and the whole thing goes into the microwave for about 90 seconds. When it comes out, the whole tea room is pervaded with a smell of microwaved peanut butter. The marshmallow quarters have melted into unimpressive pink splats. Jamila and I peer into the mug. "It's not risen much," she observes. We decide to do it again with a little more flour and a little more rising agent. Optimistically, I push three whole marshmallows onto the batter to get a more fulsome, melted effect. 

Recipes: Some simple ingredients that can be used for a mug cake.
Recipes: Some simple ingredients that can be used for a mug cake. Photo: Jamila Toderas

This time, the cake rises. It rises so much it thrusts out over the top of the mug and the marshmallows, predictably, ooze over the side in a delectable but disturbing way. 

Taste test: It's pretty good for a cake made in a microwave that's covered in melted marshmallows. It's properly peanutty, more like a muffin than a fluffy cake. The only problem is the marshmallows are a gooey, sugary mess that doesn't really go with the peanut butter cake.

M&M cookie

This one looks gorgeous in the book: a golden disc studded with colourful M&Ms. The recipe is much easier than the peanut butter cake. It only takes about five minutes to prepare rather than 10 minutes but it gives us as much of a workout as the marshmallow mug cake. The batter, again, is a rather tough dough. It's hard to press down neatly in the bottom of the mug and Jamila has to get in with her fist and punch it flat. The recipe calls for four M&Ms cut in half and pressed into the dough. This seems parsimonious so we just scatter on a layer of mini M&Ms.


It cooks in no time – only a minute. Sadly, the microwave has done strange things to the crisp outer shells of the chocolates. They're discoloured and have leaked all over the cookie, which has to be coaxed out of the bottom of the mug with a knife.

Taste test: Maybe we worked the dough too hard. "Mmmm," says night reporter Ben Westcott. "That's a very dry cookie." Our boss walks into the Fairfax Test Kitchen to make a cup of tea. We offer him the chance to take part in the test. "I don't fancy the mouldy look on the outside of that one," he observes.

Chocolate fondant cake

The chocolate fondant requires an egg yolk, lashings of cocoa powder and melted butter, and a spoonful of cream. It cooks terrifyingly in the microwave, threatening to volcano over the top of the mug and cause a chocolatey explosion. I have to hover anxiously at the microwave like a contestant on an extremely low rent version of Great British Bake Off. A couple of times I have to pause the machine when the fondant starts foaming over the side of the mug. A slight smell of burnt chocolate permeates the tea room – sorry, Test Kitchen.

Taste test: Results are extremely mixed. There's a jelly-like consistency to the fondant, but it's got a good chocolate hit and looks pretty once dusted with icing sugar and decorated with sliced strawberries. But Jamila reckons all she can taste is egg. Karen Hardy, the editor of Relax, says it's quite pleasant, like a microwave chocolate self-saucing pudding. It's probably not good that I burnt the chocolate and if we'd cooked it just a little less then it would be properly gooey in the middle (microwave times vary according to the power of each machine). "I'm getting maple, I'm getting cloves, I'm getting autumn days," says Westcott, before we tell him to bugger off.

In summary: The mug cakes aren't a total disaster. They're a great idea, and they are very easy to whip up once you've got the ingredients. They slide smoothly out of the mugs (not much scraping required) and we're warned in advance to eat them straight away. With a bit of tinkering and learning how to work each recipe with the Fairfax microwaves, we could probably get a decent result out of our favourite cakes. But do we really want to spend that much time trying to make cakes in our coffee mugs? And who keeps eggs in the tea room? I think they'll work better at home as a fun weekend project with the kids, who won't mind if the microwave does funny things to their M&Ms, or if the fondant overruns the mug. I take the cookbook home and resolve to test further recipes. A mug cake before bed with my favourite TV show sounds tempting.

Mug Cakes, by Lene Knudsen, is published by Hardie Grant and available in stores nationally. $19.95.

Chocolate fondant mug cake


1 thin slice of butter (10g)
1 egg
4 tbsp castor sugar
½ tsp vanilla sugar
3 tbsp unsweetened cocoa powder


1 square of milk chocolate
Raspberries (optional)
Small meringues (optional)

Melt the butter in a bowl in the microwave for 10 seconds (800 watts). In a mug: beat in one by one the egg, sugar, vanilla sugar, melted butter and cocoa. Cook in the microwave for 1 minute (800 watts). Decorate with the square of milk chocolate, chopped, a few raspberries and a small meringue.

From Mug Cakes, by Lene Knudsen, published by Hardie Grant. $19.95