Recipe / Overnight oats
Overnight oats with ComFoo: a banana jar step by step
One recipe, clear basic measurements and optional additions. Prepare the banana jar cold and scale quantities when making several identical jars.
Read the guide
A banana jar to prepare: mix rolled oats, milk or a plant-based drink and a mashed ripe banana. Refrigerate for at least four hours, preferably overnight. ComFoo is an optional flavour addition in this recipe.
Ingredients for one jar
The recipe suggestion has not yet been kitchen-tested. The basic measurements below are preserved from the existing recipe. We state no measured preparation time, finished serving weight or nutritional total.
- 1 dl rolled oats.
- 1 dl milk or plant-based drink.
- 1 ripe banana, mashed.
- Optional: 1 tbsp chia seeds, 1 tsp honey, a pinch of salt and 1 tbsp ComFoo.
You need a clean jar with a lid, a spoon, a decilitre measure and something to mash the banana with. Choose a jar with room to stir; no minimum jar volume has yet been measured for this recipe.
Method – the same recipe step by step
- Mash the ripe banana and put it in a clean jar.
- Add rolled oats and your chosen milk or plant-based drink.
- Stir in whichever optional ingredients you want. Mix thoroughly so everything is moistened.
- Put on the lid and refrigerate for at least four hours, preferably overnight.
- Stir before serving. Assess the texture and add a little extra chosen drink if desired. Keep chilled until eating.
Storage and serving
Mix with clean utensils and refrigerate the jar. The Swedish Food Agency describes 4 °C as a good refrigerator temperature. Prepare for the next meal and keep the jar chilled until serving. To take it to work, refrigeration needs to work during transport and at the location.
Scaling to four jars does not mean four days' shelf life has been investigated. Drink, ingredients, hygiene and temperature affect storage. Follow each ingredient's labelling and make no more jars than you can handle with proper refrigeration.
The same basic recipe for several jars
| Ingredient | 1 jar | 2 jars | 3 jars | 4 jars |
|---|---|---|---|---|
| Rolled oats | 1 dl | 2 dl | 3 dl | 4 dl |
| Chosen drink | 1 dl | 2 dl | 3 dl | 4 dl |
| Ripe banana | 1 item | 2 items | 3 items | 4 items |
| Optional ComFoo | 1 tbsp | 2 tbsp | 3 tbsp | 4 tbsp |
You can distribute directly into separate jars so each gets the same basic quantities. The table shows multiples of the original recipe, not a new recommendation for meal size.
Banana, chia and powder change the mixture
Banana size and ripeness, the drink and your optional additions may change the result. We have not conducted a comparative texture trial and therefore describe no addition as a proven optimal recipe. Start with the basic mixture to assess one change at a time.
Note what you actually used, how long the jar stood and which texture you liked. Distinguish your taste notes from a nutrition claim. A tablespoon of powder is still a small recipe quantity and does not establish that the entire jar is nutritionally complete.
Milk, plant-based drinks and optional additions
For a plant-based choice, select a plant-based drink and omit honey. Read the ingredients in the oats, drink, powder and any topping. Different plant-based drinks can contain different allergens and give different taste and contents. Replacing a drink does not automatically create an allergy-safe version.
When does a cold jar suit?
It suits a practical preparation route when you have refrigeration and want to eat with a spoon. Need to mix at the location instead, or have no refrigeration? The breakfast guide compares three possible morning routines. For hot porridge and other ComFoo recipes, see the separate recipe workshop; this page stays with the banana jar.
What remains to test
To call the recipe kitchen-tested, we need to make the same mixture, weigh the banana, measure the jar and temperature, document resting and photograph the steps. Until then, it is a recipe suggestion. Nutritional data for the whole jar also requires precise weights and declarations for the chosen ingredients. No Recipe schema with invented times or calories has been added.
Questions about the banana recipe
Can I leave out ComFoo?
Yes. It is an optional tablespoon of flavouring in the preserved basic recipe.
Do three jars show a different serving?
No. Three jars use the same basic measurements multiplied by three: 3 dl oats, 3 dl chosen drink and 3 bananas.
Will four jars keep for four days?
This has not been tested. More jars do not mean the recipe's shelf life has been investigated. Follow refrigeration advice and each ingredient's labelling.
Sources and supporting information
- Swedish Food Agency: storing food correctly – refrigeration and labelling.
- ComFoo's recipe workshop – other recipe suggestions, separate from this banana jar.
The basic recipe is preserved. Rewrite and source check: 30 September 2026. Kitchen testing, our own recipe photos and verified times remain outstanding.