If you need more high protein low carb breakfast ideas, try these make ahead omelets in a jar or cup. They are filled with tasty breakfast sausage, peppers, spinach and cheese. Just mix, bake and store in the refrigerator for a healthy breakfast on the go all week. Each omelet cup has only 3.1g net carbs and 16.3g protein.
You might also like these 5 easy keto omelets post!

Today I am updating a very old recipe. Originally I made these sausage, spinach & pepper omelets in small mason jars and baked them in the oven. I’ve since found that people are nervous about baking things in mason jars so I’ve revised the recipe to be lower in carbs and I used tempered custard cups which work great.
The idea is that these are make ahead omelets in a glass cup that you can bake in the oven and have ready for a healthy low carb breakfast on the go! They are very tasty and a good way to stay on your low carb diet.
I’m including the information about the mason jars for anyone that might come back here for that recipe but I recommend using the custard cups instead.
Ingredients For These Make Ahead Omelets
I picked the following ingredients for flavor, color and low carbs. I used breakfast sausage, peppers, spinach, cheddar, heavy cream and eggs. If you are just doing this for meal prep and don’t care about carbs pick your own favorite omelet fillings.
Since I’m updating this recipe, I used cream instead of yogurt for low carbs but you can stick with the yogurt if you wish. I also doubled the spinach for more bulk and nutrition.
Let’s Make Some Omelets In A Cup!
Start by browning the sausage and peppers in a non stick skillet. Once the sausage is browned and the peppers soft, turn off the heat and slowly mix in the spinach until it’s starting to wilt. See the picture below to see how it should look.
Add the cups to a cookie sheet and spoon some of the sausage mixture into each cup. I only had 4 custard cups so I used 2 ramekins(6oz) in addition to the cups. Next whisk the eggs, cream and half of the cheese. Pour over the sausage mixture and top with the remaining cheese.
Bake them in the oven for 15 minutes. Don’t worry if they are not completely cooked because when you reheat them they will cook a little more. They should be mostly cooked though. If they are just a little loose in the middle that is ok.
Let them cool before you add the lids and then store them in the refrigerator. To eat them later in the week, just take off the lid and cook for 30 second intervals until heated through. They should really take no more than 30-60 seconds to reheat.
Mason Jars, Custard Cups Or Ramekins?
Below are the custard cups that I recently bought and really like for this recipe. I like that they have lids, they are made of tempered glass (oven proof) and they are a good size for meal prep.
My old recipe used 8oz jars and there was some discussion as to whether you can use mason jars in the oven. I had no problems but I didn’t want you all to have any issues so I switched this recipe to use the custard cups.
Another option is to use ramekins which are made for the oven. Some even have lids. Here is what the ramekin looks like below. I used 6oz ramekins.
So if you are looking for more low carb breakfast ideas try these make ahead omelets. They really are tasty, healthy and very easy to make ahead for breakfast all week. They are also high in protein and just overall very tasty.
The nutritional information for the 1 omelet cup is:
297 cals / 24.1g fat / 3.8g carbs / 0.7g fiber / 16.3g protein = 3.1g carbs net carbs
Old comments regarding the omelets in mason jars
Disclaimer: One reader pointed out that you should not put mason jars in the oven. I was unaware of this when writing the post. And while I had no trouble I understand that the type of glass that mason jars are made of can not withstand large temperature fluctuations which may cause it to break. Here is an article I found that says you can bake in jars if you use a water bath. I have not tried it but I wanted you all to be aware of the risks.
Notes from Readers:
Colleen P: “I made 30 jars for breakfast at our retreat and each one was eaten up. I got many complements on the uniqueness of this idea. I used eggs, cheese, spinach and sausage. I will use this recipe again. I did 12 at a time and it took much longer, about 30 mins each, but was able to keep them warm by simply putting a towel over the done ones. Also, I used water instead of milk or yogurt. I have always found water makes eggs fluffier. ”
Another reader pointed out that these are ½ pints. If you are using larger jars, you will have to use more of the mixture and it may take longer to cook.

Make Ahead Omelet in a Jar or Cup with Sausage, Peppers & Spinach
This omelette in a jar recipe is perfect for a high protein and low carb breakfast on the go. Make ahead and eat all week.
Ingredients
- 1 cup chopped sweet peppers
- 1 cup cheddar
- 2 cups spinach, chopped
- 7 eggs
- ½ cup heavy cream
- 4 oz breakfast sausage, uncooked
Instructions
- Preheat oven to 350F.
- In a skillet,add sausage and peppers and cook until the peppers are soft and the sausage is brown.
- Add your spinach and turn off the heat. Mix the spinach around until it's wilted.
- In a bowl, whisk your eggs and cream. When they are mixed well, add half of the cheese.
- Spray six custard cups or ramekins with cooking spray.
- Add the susage mixture to each of the cups. Then pour in the egg mixture.
- Top each of the jars with the remaining cheese.
- Place the cups on a cookie sheet and bake for 15 minutes. If the middles are a little loose that is ok becuase you will be reheating these and they will cook some more. But they should be mostly done.
- Let cool and then add your lid and store in the refrigerator or eat.
- To reheat, place in th microwave for 30 seconds or until warmed through.
Notes
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Nutrition Information:
Yield: 5 Serving Size: 1 ServingsAmount Per Serving: Calories: 297
Leslie says
Hello,
I’m confused as to baking in mason jars, is it required to put a little water inside the pan while the mason jars are baking in the oven?
Denise says
Hi Leslie,
Sorry if this is confusing. I did not use water and I had no problems. However mason jars are not made from tempered glass so if there is prolonged heat or if you put piping hot food into a room temperature glass it could shatter.
The reference I sited in the post is no longer there but for some reason Google still shows her site for answering the question about baking in a mason jar and this is what it says:
“Place Mason jars in a tall-sided roasting pan or baking dish and fill pan or dish with hot water. Pint-sized Mason jars will take 25 to 30 minutes while quart-sized Mason jars will take 50 to 60 minutes, depending on the baked good.”
If you want to use a water bath that might be a safer route. Or you could put these in a the microwave for 30 second intervals until they are done. I have a post that I did that with (western omelet in a jar).
Hope that helps you. Let me know if you have any other questions.
Ellen Sackett says
Can you tell me how long to reheat these in the microwave? Thank you.
Denise says
Hi Ellen, if they are already cooked, you would only need 30 -60 seconds in the microwave. Enjoy!
Renee' says
Instead of cooking in the oven, can you cook these in the microwave?
Denise says
Hi Renee, yes you can. I wrote a post here about it. https://mylifecookbook.com/western-omelet-jar-microwave/
“HOW LONG SHOULD I COOK THESE IN THE MICROWAVE?
First of all you don’t want to place these in the microwave with the metal lid. Shake well before cooking and then take off the metal lid. Start with 1 minute. Watch to make sure it doesn’t over flow. Then put it in for another minute and open it when it looks like it might over flow. You might have to do this a few times if you are using the 8oz jar. All in all it might take up to 2 minutes and that’s all. “
Ann Knickerbocker says
I think first of all you want to shake it THEN take the metal lid off! lol (Sorry. Retired reporter/editor here.)
Denise says
Thank you! I’ve fixed it.
Jennifer says
Thank you. I learned so much from your recipe and also the others who posted. Our family is a keto Family. You have enriched our cooking and eating experience.
Our son, too, is in the Army. He will love some baked goodies.
Denise says
Hi Jennifer. I hope you and your family enjoy these!
Whitney says
I made these for a work week, five jars on a Sunday night and paired with candied pecans some days and sweet potatoes with brown sugar on other days. I wasn’t sure about leaving just the mixture in the jars in the fridge but baking them and allowing them to cool and then refrigerating worked well and lasted five days. Sooooo good. And I’m the same way with eating breakfast: if it’s not ready, I’ll just skip it and wait for lunch. Lol thanks for this idea !
Denise says
Hi Whitney, so glad they worked for you! Thanks for stopping by and sharing your tips and ideas. I’ve been eating egg muffins lately because I can freeze them and heat them up in the microwave quickly. However you reminded me that I should make these again. Enjoy the rest of your weekend!
Sandra Vassar says
I would like to know how long these will last? Do they have to be refrigerated?
Wanted to make them for Christmas gifts.
Denise says
Hi Sandra, if you are talking about them being uncooked in the fridge I would say a day or so. Sometimes the eggs separate or get a bit watery. If you are cooking them, I would not do more than a day. Since you are giving them as gifts maybe do a dry run with just one jar? Sausage just a little bit of the veggies and sausage and use an egg or two. I would also suggest using cream instead of yogurt as yogurt has more water in it. Sorry I’m not of more help.
Becky says
About baking with Mason jars: when my son was deployed overseas I joined a group called Proud Army Moms. They taught me how to send my son baked goods in Mason jars! They work very well, they re made to withstand high heat. Fill them 2/3 full with any batter – cake, muffin, quick bread, etc., and bake. When they come out of the oven put the lids on right away. You’ll hear them pop when they seal. I sent over a dozen cases of Mason Jar Cakes to my son and never had a problem with a single one!
Denise says
Oh that’s great to know! Thanks for sharing and helping my readers! I love to eat out of jars and that sounds great what you did for your son.
Jan Patenaude, RD, CLT says
WONDERFUL INFO! Bless and Thank your son for his service – and yours too.