These Cosmic Brownie Overnight Oats are a crazy delicious play on the nostalgic treat – but with over 40 grams of protein and 11 grams of fiber.

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As a meal prep-loving dietitian, I’m a huge fan of overnight oats. I mean, clearly – I’ve got loads of popular overnight oats recipes on my website! (You’ve got to try my cinnamon roll overnight oats and biscoff overnight oats!) But truly, these cosmic brownie overnight oats are my new personal favorite.

Why You’ll Love Cosmic Brownie Overnight Oats

There’s a fudgy, brownie overnight oat base, topped with a protein-packed chocolate “frosting” layer.
The candy coated mini chocolate chips sprinkles are such a nostalgic topping.
They’re so much fun to eat!
SO delicious!
You only need about 10-15 minutes of hands on prep time. The fridge does the rest of the work!
Packed with protein – 44 grams, with the ingredients I used!
Full of fiber – 11 grams!
Family friendly – the whole family loves these!
They keep you full for hours!

Ingredient Notes & Substitutions

For a full ingredient list with quantities, please check out the recipe card at the bottom of this post.

ingredients to make cosmic brownie overnight oats

Old-Fashioned Oats: It does need to be old-fashioned oats, as neither quick oats or steel cut oats absorb moisture the same, so the resulting overnight oats will be a different consistency. Be sure to use certified gluten-free oats if you need them!
Chocolate Protein Powder – I’m a HUGE fan of Clean Simple Eats Brownie Batter Protein Powder in this recipe! But of course – use what you like or have on hand!
Cocoa Powder – specifically Dutch-processed cocoa powder. It’s a little less bitter than traditional cocoa powder, and lends a richer taste and deeper color, to really get more of a fudgy brownie vibe.
Chia Seeds – a fantastic source of fiber, healthy fats, and more protein.
Flax Seeds – another great way to boost the healthy fats and fiber of these overnight oats. Be sure to use ground flax seeds for better nutrient absorption.
Greek Yogurt – I use plain, fat-free Greek yogurt to both add more protein and help make the overnight oats even creamier and fudgier.
Milk – you can use any milk you prefer! I used 1% milk personally, but even plant-based options like almond milk work fine (but will slightly decrease the protein).
Sprinkles – are they even cosmic brownie inspired overnight oats if they don’t have the classic Candy Coated Chocolate Sprinkles?!

How to Make Cosmic Brownie Overnight Oats

For complete instructions, please check out the recipe card at the bottom of this post.

whisking together the ingredients to make cosmic brownie overnight oats

the chocolate high protein "Frosting" for the cosmic brownie overnight oats

Add all the ingredients for the fudgy brownie base layer of the overnight oats to a small jar and whisk together. Next, whisk together the frosting ingredients.

adding the "frosting" layer to the cosmic brownie overnight oats

candy coated chocolate sprinkles on cosmic brownie overnight oats

Pour the frosting on top of the oats and spread/ shake it into a smooth layer. Refrigerate overnight, or at least four hours, then sprinkle the candy coated chocolate chips on before serving. Enjoy!

Tips and Variations

You can add the sprinkles before refrigerating, but it’s not a true “frosting” and the moisture in it will make the candy coating bleed. They’ll still taste great, but if you want a prettier look, wait to add the sprinkles until right before eating.
Need even faster meal prep? Skip the frosting! The overnight oats still taste amazing without. The frosting layer adds more protein, a contrast in texture, and that nostalgia of the childhood frosted brownie treat.

meal prep jars of cosmic brownie overnight oats

Storage, Freezing, & Reheating

Overnight oats are a perfect meal prep breakfast option. They can be kept in airtight containers in the refrigerator for 4-5 days.

I don’t suggest freezing these cosmic brownie overnight oats, due to the different layers and freezing affecting the consistency of the frosting layer, especially.

I personally typically enjoy my overnight oats chilled, but you can reheat them! If you’re going to reheat these cosmic brownie overnight oats, I’d suggest waiting to add the frosting layer and sprinkles until after you’ve heated the base oats. You may want to add another 1-2 tablespoons of milk, depending on how long they’ve been in your fridge. Then microwave for 60-90 seconds.

Are Overnight Oats Healthy?

Overnight oats can absolutely be an incredibly nutrient-dense, healthy option. Yes – even dessert-inspired ones, like these! They’re full of fiber, packed with protein, loaded with heart healthy fats, and I make mine so they are limited (or don’t have any) added sugar.

You can read more in my article, “Are Overnight Oats Healthy?” (This article also addresses unfounded concerns over the safety of consuming oats and phytates without the oats being cooked – spoiler, it’s fine!)

a spoonful of rich and fudgy cosmic brownie overnight oats

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