Fruity Pebbles Protein Mug Cake

This mug cake is packed with protein and bursting with fun flavors!
Servings: 1
Jump to Recipe
Time: 10 mins

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Mug cakes are all the rage, and this Fruity Pebbles Protein Mug Cake is low carb, high protein, and ready in minutes!  Can it get any better??

Fruity Pebbles protein mug cake in a white mug with frosting on top.

Fruity pebbles cereal is the best out there. It’s my favorite childhood cereal, favorite adult cereal, favorite cereal in general. That’s why we had to make this fruity pebble mug cake, and of course we packed it with protein. If you’ve been on our site, you’ve probably seen our fruity pebble protein bars that are all the rage, thanks to this classic cereal!

For this mug cake recipe, we use protein powder as a substitute for flour to keep it low in carbs and big in flavor. In a typical baked good, you need some flour to ensure the cake rises, but in mug cakes we have a much higher percentage of leavening ingredients to protein so the protein powder works just fine. The best part is that little cake has 8 grams of protein!

For the big flavor, we soak the fruity pebbles in the milk to really enhance that sweet cereal milk flavor! Wait, did you say you want more high protein Fruity Pebble recipes? No worries, try some of our other fruity pebbles protein powder recipes: Fruity Pebble Protein Pancakes, Fruity Pebble Protein Cereal Bars, or Fruity Pebble Protein Ice Cream!


Table of Contents



Ingredients and Substitution Options

Fruity Pebbles protein mug cake ingredients on a concrete table.

All substitution options are a 1:1 substitution unless noted otherwise.

Fruity Pebbles:  The star of the dish! Fruity pebbles are also great because they are pretty low in carbs and gluten free by nature, however they are processed in a gluten facility so they cannot be certified as gluten free.

Substitutions: Cocoa Pebbles or Frosted Flakes are also great cereals! You van also use your favorite cereal and then strain out the milk to just use the cereal milk and leave out the whole cereal pieces in the recipe.


Milk: Milk is necessary for this protein cake because protein powder absorbs so much liquid. We use coconut milk for ours due to its lightness and mild coconut flavor.

Substitutions: Your favorite unsweetened plant milk (unsweetened almond milk, coconut milk, rice milk, etc.) or cow’s milk can be used. Check out our post on substituting oat milk here!

Coconut Oil:  This is our fat in the cake. Fat helps to blend flavors and enhance flavors, like Fruity Pebbles! We love coconut oil because it gives a mild coconut flavor and some good healthy fats.

Substitutions: Avocado oil, melted butter, or another mild vegetable oil can be used. You can try using greek yogurt for more protein as a substitute too, since it is a fat, but it has not been tested.


Vanilla Whey Protein Powder: The key ingredient making this a protein mug cake! We chose vanilla protein powder because it mixes well and acts similarly to flour. There is even Fruity Pebbles Protein Powder that you can buy here that is a great substitute for vanilla!

Substitutions: Any of your favorite whey protein can be used. Using different flavors will result in a totally different recipe. For example, chocolate protein powder will get you a chocolate cake!


Baking Powder: Baking powder provides the rise. It is a combination of baking soda (a base) and cream of tartar (an acid) that is activated with liquid.

Substitutions: You can make your own baking powder by mixing one part baking soda to one part cornstarch and two parts cream of tartar. You can also add an additional ¼ of a cup of yogurt and use ½ tsp of baking soda in place of the baking powder.


Pure Vanilla Extract: Vanilla is the essential baking ingredient. Like fat, it enhances other flavors and adds buttery notes without actually adding more butter.

Substitutions: You can use ¼ tsp of almond extract or butter extract or omit it all together. Imitation vanilla can also be used.


Coconut Sugar: Just a smidge more sweetness! A spoonful of sugar, you can say. Coconut sugar helps to add some warm notes to an otherwise fruity dish, like adding brown sugar to grapefruit – yum!

Substitutions: Brown sugar, white sugar, agave, or maple syrup can be used.


Egg: Eggs are the binder, or glue. When mixed in, eggs help keep all the ingredients together. Once cooked, they expand to create more air pockets for the baking powder reaction to occur in.

Substitutions: Flax eggs or egg replacer, like this one from Bob’s Red Mill or one from Just Egg, can be used as an egg substitute. A banana, applesauce, and many other things can be used also. Check out our post of egg substitutes here!


How to Make a Mug Cake

Step one: Pour milk and half of the cereal into a LARGE mug and let sit for 5 minutes.

Step two: After 5 minutes, add remaining ingredients to the mug and mix well. No need to mix dry ingredients and wet ingredients separately!

Step three: Microwave for 70-90 seconds, keeping an eye on it so it does not overflow. Let sit for 1 minute in the microwave before enjoying. The mug will be SUPER hot!!


Watch How to Make This!


Joy Tip!

Use a tall mug! Using a large mug is critical for mug cakes because they have so much leavener. Try to use one that is double the height as it is wide and at least three inches in diameter. Using a large mug is an easy way to make sure your cake doesn’t overflow.


Quick Facts and Common Questions

How do you make a mug cake not rubbery?

Mug cakes are notorious for being rubbery because all of the ingredients are mixed at once and typically over mixed. This means the gluten is developed and then cooked quickly, resulting in a rubbery cake. Because we are using protein powder, which does not develop gluten when over-mixed, the risk of a rubbery cake is much lower.


Why are mug cakes spongy?

A microwave mug cake usually has more leaveners than a typical cake to help it rise quickly. This is why a mug cake can be spongy in texture.


How does protein powder affect baking?

Whey protein powder typically does well in baking. Because it absorbs liquid and expands like flour, you can typically use 1/3 of a cup of whey protein to replace up to a cup of flour in more forgiving baked goods. Other protein powders, or too much powder can result in a dry, chalky texture.


Which is better – plant protein or whey protein?

For baking – it depends. Whet protein has less fiber than plant protein, and thus absorbs less water. Either are fine for baking, but if using plant protein when a recipe calls for whey, add 25% more liquid than the recipe calls for. If using whey protein when a recipe calls for plant, reduce the liquid by 25%.


Can I use Fruity Pebbles Protein Powder?

Sure can! Fruity pebble protein powder is supposed to have the exact taste of fruity pebbles so we think this would be a fabulous addition to the mug cake!


Want to Save This For Later? Here’s How!

To store your mug cake for later, simply cover it tightly in plastic wrap or an airtight container. Next time you are ready to reheat it, just microwave in 10 second intervals. Be careful to not overcook it to ensure you end up with a moist cake!


Fun Fact! 

Fruity Pebbles were introduced to the world in 1971. They were adapted from the cereal, Sugar Rice Krinkles and the original name was Flint Chips and Rubble Stones. They are is the oldest surviving cereal based on a TV show (for good reason!). Originally they only had 3 flavors, orange, lemon, and cherry. In Canada, they have different shapes all together. What’s your favorite cereal? (Source)


Try these other delicious recipes!

Honey Mug Cake (Gluten Free)

Cheesecake Without Cream Cheese

Gluten Free Lemon Cake

Eggless Pumpkin Pie


Did you try this and love it? Leave us a review, we would love to hear from you!


Fruity Pebbles mug cake in a white mug on top of a white plate.

Fruity Pebbles Protein Mug Cake

Servings: 1
Total Time: 10 minutes
Mug cakes are all the rage and this Fruity Pebbles Protein Mug Cake is low carb, high protein, and ready in minutes.  Can it get any better??
5 from 3 votes
Print Pin Rate
Course: Dessert
Cuisine: American
Keyword: cake, cereal, fruity pebbles, microwave, mug, protein, protein powder
Prep Time: 8 minutes
Cook Time: 2 minutes
Total Time: 10 minutes
Calories: 336 kcal



  • Pour milk in cup and add half of the fruity pebbles to it and let sit to flavor the milk.
    Fruity Pebbles cereal sitting in milk in a glass bowl.
  • After 5 minutes, add remaining ingredients and mix well to combine.
    Fruity Pebbles cake batter mixed together in a glass bowl.
  • Microwave for 70-90 seconds and let sit in microwave for 1 minute before consuming.
    Fruity Pebbles cake batter in a white mug.



Nutritional information is an estimate and for informational purposes only.


Calories: 336kcal | Carbohydrates: 30g | Protein: 27g | Fat: 12g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 1g | Cholesterol: 233mg | Sodium: 491mg | Potassium: 286mg | Fiber: 1g | Sugar: 16g | Vitamin A: 586IU | Vitamin C: 2mg | Calcium: 373mg | Iron: 2mg
Did you try this? We'd love to hear how it went. Please leave a review below! Or, follow and tag us on Instagram!Mention @_Joytothefood_ or tag #joytothefood!


  1. Brit

    5 stars
    Nice easy dessert that hit the spot 🙂

  2. Cass

    5 stars
    Perfect quick dessert! I did have trouble deciding what size mug to use, what size do you recommend?

    • Mika

      Hello! That’s a great question, we find that a 3″ diameter and slightly taller mug is best because it allows for expansion. You want a big mug to avoid overflowing!


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Welcome to Joy to the Food! We’re so glad you’re here. We’re Mika and Dan, and the two Nalas (our spunky pups). We’re all about easy and affordable recipes that bring joy to the kitchen and make life stress free!