This protein mug cake is a follow on recipe from my whey protein mug cake. While the original recipe is designed to be made with WPI, this mug cake uses a plant protein. Why? Firstly, because WPI is a quite a thirsty protein that needs a specially designed recipe. Secondly, variety! Not everybody can have dairy, so I wanted to develop a protein mug cake that works for dairy free people.

An aerial view of a protein mug cake topped with two small scoops of vanilla ice cream. The mug cake is in a white speckled ceramic mug on a white speckled ceramic plate

Protein mug cake (dairy free)

Name: Protein mug cake (dairy free)
Prep time: 5 min
Cook time: 1 min
Ingredients: 75g (1/2 1 large) ripe or just ripe banana, mashed; 30g plant protein (see body of post for tips); 1 extra large egg (45-55g weighed out of shell); 25g nut or seed butter of choice (see notes); 1/8 tsp baking soda; 1-2 tsp vegetable or neutral oil (see body of post); 1 tsp vinegar or lemon juice; 20-40 ml (1-2 Australian tablespoons)* plant milk of choice

This mug cake uses a plant protein, an egg, nut or seed butter, a little bit of oil and banana. It uses baking soda and vinegar or lemon juice for leavening. The mug cake is moist and ready in 5 minutes. It is naturally sweetened using the banana (and potentially your protein powder).

The mug cake is filling and quick to make. I have tested it with a number of plant proteins, which I will go into below. It contains no added sugar (protein dependent) but has plenty of sweetness from the banana. Depending on the protein you use, it tastes like a high protein banana bread.

A sunlit aerial image of a protein mug cake with chocolate chips and a small scoop of vanilla ice cream. The mug cake sits in a white speckled mug atop a white speckled ceramic plate.

Can I use whey protein isolate in this protein mug cake?

In my testing, I found that WPI and egg together easily make for a spongy mug cake with a weird texture. This is particularly the case with WPI that doesn’t use xanthan gum, inulin or any fibres or binders. I choose to use a plain WPI because of my sensitive digestive system – I don’t want or need those extra gums.

If you’d like to use WPI, I recommend using my recipe for a whey protein mug cake specifically. I developed the recipe using pure WPI (with no additives) so it should also work with WPI containing additives.

An aerial close up view of a white speckled ceramic mug filled with a protein mug cake. The mug cake is topped with banana slices and a spoon sticks into the cake, revealing the gooey, cakey interior. The mug sits on a white speckled ceramic plate which forms the backdrop

Which plant proteins work in this recipe?

I have tried 100% hemp protein, sunflower seed protein, soy protein and Macro Mike in this recipe. I didn’t love the sunflower seed or soy protein options, but they do work.

From experience, it’s easier to use a protein with binders than it is a pure protein. As such, I developed this recipe to work with a pure protein, because then it works with everything!

One thing I have noticed is that different proteins vary dramatically in how dry they bake up. As a general rule, those with gums and inulin or other additives bake up a little less dry than the pure blends.

I have found hemp seed protein to need far less liquid than soy protein. Sunflower seed protein sits in the middle, but it can turn green when it reacts with baking soda.

Peanut protein is on the drier side, although less dry than WPI. A mug cake with peanut protein or soy protein benefits from the optional 1-2 teaspoons of neutral oil.

An aerial sunlit image of the ingredients used for gluten free protein mug cake. A banana, egg, baking soda, oil, nut butter and protein powder are all arranged in small bowls on a white marble table.

Can I omit the banana?

Not at this stage, no. As I test more mug cakes I will be sure to update the post with more options. You could try replacing the banana with pumpkin puree, but I haven’t tried that myself.

An aerial view of a protein mug cake topped with melting vanilla ice cream and melted chocolate. The cake sits in a white speckled ceramic mug which sits on a dark metal steel backdrop

Tips for your protein mug cake

Every microwave works differently, so it’s best to undercook your mug cake slightly and check it as you go. Luckily, plant proteins don’t tend to create the same spongy texture as over-cooked whey mug cakes, but over-cooked eggs do.

Some proteins don’t need any oil and some do. Just like gluten free flours, they have varying levels of dryness and texture once baked. I’ve provided a bit more information in the protein section, noting that I have tested mostly pure proteins rather than blends.

Sunflower seed protein and nut butter can turn green when combined with baking soda. Nothing harmful, just something to be aware of!

I currently have not tested substitutes for the banana. I do have a recipe for a vegan protein mug cake, though (for those who need an egg free option).

You can add chocolate chips, berries, a nut butter centre, some Nutella, or anything you like. If you don’t need the mug cake to be gluten free, you could also use Biscoff spread.

A side on macro close up image of a protein mug cake filled with melty chocolate chips. The front part of the mug cake has been eaten, revealing the melty chocolate and crumb within. The cake is in a white speckled ceramic mug.

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