Mocha Protein Mug Cake with a Melting Chocolate Middle (Vegan, Decaf)

This mocha protein mug cake has about 28 g of protein, a melting dark chocolate middle and takes about 5 minutes, including 90 seconds in the microwave. It's vegan, made with half coffee and half chocolate protein powder, and the coffee is decaf. That makes it a warm, chocolatey option for cold, rainy evenings, even after dinner.

What you'll find here: the recipe, a protein breakdown, how to keep a protein mug cake from turning rubbery, a note on caffeine, flavour swaps and answers to the most common questions.

Makes	1 mug cake
Prep time	3 minutes
Microwave	60 + 30 seconds at 800 W, plus 1 minute to rest
Protein	about 28 g
Free from	eggs, dairy

Ingredients for a mocha protein mug cake

You need nine ingredients, and the two protein powders do most of the work. Use a big mug or a microwave-safe glass that holds at least 350 ml, because the cake rises a lot before it settles.

• 15 g WAM Protein Iced Coffee
• 15 g WAM Protein Chocolate Hazelnut
• 25 g oat flour (or oats blended into flour)
• ½ tsp baking powder
• a pinch of salt
• 1 tbsp maple syrup (more or less to taste)
• 10 g almond butter (about 2 tsp)
• 80 ml oat drink
• 1 square of dark chocolate (about 10 g)

Why these ingredients? Oat flour gives the cake structure, so it doesn't collapse into a protein pudding. Almond butter adds fat, which keeps it soft. The salt makes the coffee and chocolate taste deeper, and the chocolate square melts into a warm middle.

Method: how to make a mocha protein mug cake

1. Put both protein powders, the oat flour, baking powder and salt into a big mug or microwave-safe glass and mix.
2. Add the maple syrup, almond butter and oat drink and stir until smooth. The batter is very thick, closer to a brownie dough than a cake batter. Smooth the top with the back of the spoon.
3. Push the chocolate square into the middle and smooth the batter over it.
4. Microwave for 60 seconds at 800 W.
5. Let it stand for a moment so it can set, then microwave for another 30 seconds. The top should look set and just a little moist.
6. Let it rest for 1 minute before you dig in. It keeps cooking, and the melted chocolate cools down from scalding to warm.

Every microwave is different. At higher wattage, start with 45 seconds and check after the first round.

How much protein is in this mug cake?

This mocha mug cake has about 28 g of protein, and more than three quarters of it comes from the two protein powders. Here's how it adds up, using standard nutrition values for the basic ingredients:

Ingredient	Amount	Protein
WAM Protein Iced Coffee	15 g	11 g
WAM Protein Chocolate Hazelnut	15 g	10.5 g
Oat flour	25 g	3.5 g
Almond butter	10 g	2 g
Oat drink and dark chocolate	80 ml + 10 g	1.5 g
Whole mug cake		about 28 g

A classic chocolate mug cake is just as welcome on a cold evening. This one is simply another option: if you'd like a little more protein in your day, a dessert that brings 28 g with it makes that easier. Protein contributes to the growth and maintenance of muscle mass.

Why do protein mug cakes turn rubbery?

Protein mug cakes turn rubbery when they're microwaved too long in one go. Protein sets fast in the microwave and keeps firming up after the timer goes off. That's why this recipe uses two short rounds with a pause in between, followed by a minute's rest.

"Protein sets much faster than flour, especially in the microwave. Two short rounds and a minute of patience are the difference between a soft mug cake and a rubbery one." – Dr. Anna Falk, chemist and founder of WAM

The other reason is too little liquid or fat. The oat drink and almond butter keep this one soft and moist. Expect something between a fudgy brownie and a light sponge: soft and moist, with a warm, molten centre.

Can you eat a mocha mug cake in the evening?

Yes, for most people this mug cake works well in the evening, because WAM Iced Coffee is made with decaf coffee. Decaf isn't completely free of caffeine, though: a small trace remains, and the dark chocolate square adds a little too. If you're very sensitive to caffeine, use a chocolate with less cocoa, or leave it out and make the all-chocolate version below.

Can you make it with just one flavour?

Yes, you can use 30 g of one flavour instead of 15 g of each. With only Chocolate Hazelnut it becomes a rich chocolate hazelnut mug cake with dark cocoa notes. With only Iced Coffee it tastes more like a latte-style coffee cake. Both flavours are lightly sweet, so you don't need to change the maple syrup. For a pure chocolate version, try our chocolate protein mug cake.

Variations and toppings

• Nut butter: peanut butter or hazelnut butter instead of almond butter.
• Plant drink: soy drink instead of oat drink adds about 2 g of protein.
• Toppings: a spoon of plant yoghurt, a few raspberries or a pinch of cinnamon.
• Prep ahead: mix the dry ingredients for several mug cakes in jars. On the night, add the wet ingredients and the chocolate.

If you like coffee and chocolate together, our tiramisu chia pudding uses the same decaf Iced Coffee flavour for breakfast.

FAQ

Can I make this mug cake in a glass instead of a mug?

Yes, any microwave-safe glass works, and it lets you watch the cake rise. Choose one that holds at least 350 ml, because the batter almost doubles in height before it sinks back. Thin glasses can get very hot in the microwave, so hold it by the bottom with a tea towel. A wide glass or mug also cooks more evenly than a narrow, tall one.

Can I bake it in the oven instead?

We've only tested this recipe in the microwave so far. An oven version in a small ramekin at 180 °C for around 12–14 minutes should work, but it's not tested yet. If you try it, check after 10 minutes: the top should be set and the middle still soft. Use an ovenproof dish, as not every mug or glass can go in the oven.

How can I make it sweeter or less sweet?

Adjust the maple syrup. With 1 tablespoon the cake tastes like dark chocolate and coffee, not like a sugary dessert, because both protein powders are only lightly sweetened with stevia. For a sweeter mug cake, add up to 1 more teaspoon of syrup or use a milk-style vegan chocolate for the middle. For less sweetness, halve the syrup and add a splash more oat drink.

Is this mug cake gluten-free?

No, we don't call it gluten-free. Regular oat flour is often contaminated with wheat, and we can't guarantee that WAM Protein is free from traces of gluten. Certified gluten-free oats reduce the risk, but the mug cake still isn't suitable for people with coeliac disease. If you need to avoid gluten strictly, use products that are certified gluten-free.

Can I make the mug cake ahead and reheat it?

It's best eaten fresh, while the middle is still melting. Protein mug cakes firm up as they cool and can turn dry when reheated. If you want to prepare ahead, mix the dry ingredients in a jar instead. Then it only takes a minute to stir in the oat drink, almond butter and syrup, add the chocolate and microwave it.

Can I use whey instead of vegan protein powder?

You can, but whey usually absorbs less liquid and sets faster in the microwave. Start with about 60 ml of oat drink and check after 45 seconds instead of 60. The texture tends to be springier and drier. The mug cake will also no longer be vegan. Our comparison of whey and vegan protein explains the differences.

The protein powders in this recipe

Sources

• European Commission: Regulation (EU) No 432/2012, list of permitted health claims (protein and muscle mass).
• EFSA Panel on Dietetic Products, Nutrition and Allergies (2015): Scientific Opinion on the safety of caffeine.
• USDA FoodData Central: nutrition values for oat flour, almond butter, oat drink and dark chocolate.
• WAM Protein Iced Coffee and Chocolate Hazelnut: nutrition labels.