Keto Mushroom Omelet with Gruyère and Herbs
This keto mushroom omelet delivers a complete breakfast in 15 minutes with 28 g of protein and 3 g of net carbs. Three eggs, white mushrooms fried in butter, grated Gruyère, and fresh herbs, that is all a classic mushroom omelet needs. A weekday breakfast that gets by without any specialty ingredients.
Key takeaways at a glance
- Total time: approx. 15 minutes, 5 minutes of prep and 8 to 10 minutes in the pan.
- Approx. 3 g net carbs and 32 g fat per serving.
- Ingredients: eggs, white mushrooms, butter, Gruyère, chives, parsley.
- Works as a filling keto breakfast, a light lunch, or brunch without specialty ingredients.
Ingredients
One serving is a single omelet made from 3 eggs with 120 g of white mushrooms and 30 g of Gruyère, intended as breakfast or a light lunch for one adult.
| Amount | Ingredient | Note | ||
|---|---|---|---|---|
| medium eggs | - | |||
| white mushrooms | sliced | |||
| sliced | ||||
| butter | approx. 1 tbsp | |||
| approx. 1 tbsp | ||||
| Gruyère | freshly grated | |||
| freshly grated | ||||
| chives | approx. 1 tbsp chopped | |||
| approx. 1 tbsp chopped | ||||
| parsley | approx. 1 tsp chopped | |||
| approx. 1 tsp chopped | ||||
| water | approx. 1 tbsp, cold | |||
| approx. 1 tbsp, cold | ||||
| salt | split between mushrooms and eggs | |||
| split between mushrooms and eggs | ||||
| pepper | freshly ground | |||
| freshly ground | ||||
Preparation
Slice the mushrooms, fry them in butter until golden brown, whisk the eggs, and pour them over the mushrooms. Sprinkle with Gruyère, let it set, and serve with fresh herbs.
Why this omelet fits a keto diet
Three medium eggs (approx. 165 g) provide about 21 g of protein, 16 g of fat, and only 1 g of carbs. White mushrooms (120 g) add 3 g of protein, almost no fat, and roughly 1.5 g of net carbs, along with potassium and B vitamins. Gruyère (30 g) contributes another 8 g of protein, 9 g of fat, and 0 g of carbs. Butter for frying (15 g) and the egg yolks lock in the fat ratio. Altogether the serving lands at about 3 g net carbs, 32 g fat, and 28 g protein at around 430 kcal, a classic keto ratio for a breakfast that keeps you full until lunch.
Source: USDA FoodData Central, Egg, whole, raw, fresh , USDA, Mushrooms, white, raw
Are white mushrooms keto-friendly?
Yes, white mushrooms contain only 2.3 g of carbs per 100 g, of which 1 g is fiber, leaving roughly 1.3 g of net carbs. That makes them one of the lowest-carb mushrooms and an easy fit for keto, even in larger amounts. They also deliver 318 mg of potassium per 100 g, which matters on keto because the kidneys flush more water and electrolytes during the first few weeks.
Why Gruyère instead of pre-shredded cheese?
Gruyère is a hard cheese with under 1 g of carbs per 100 g and a nutty flavor that beats freshly grated cheddar or mozzarella. In the omelet it melts evenly without turning watery, while pre-shredded cheese from a bag often contains starch-based anti-caking agents and melts poorly. If Gruyère is not on hand, mountain cheese, Comté, or a well-aged Emmental all work, with very similar macros.
How do I serve and vary the omelet?
Slide the omelet straight from the pan onto the plate, scatter herbs on top, and serve it unfolded so the cheese crust stays visible. From experience, it pays to beat the eggs vigorously with a fork rather than just stirring them, a little air makes the omelet noticeably fluffier.
Meal prep: preparing ahead and reheating
You can slice the mushrooms the night before and keep them in a sealed container in the fridge, that saves about 3 minutes in the morning. The finished omelet is best fresh, reheating turns the melted cheese rubbery and the egg whites tough. If you still want to prep ahead, keep the omelet in the fridge for no more than 1 day and warm it in a skillet (not the microwave) over low heat for 2 minutes.
Version without mushrooms
If you do not like mushrooms, swap them 1:1 for 80 g of baby spinach (sautéed with a little garlic in butter for 2 minutes) or 60 g of cherry tomatoes (halved, fried for 2 minutes). Net carbs barely change (spinach about 1.4 g, cherry tomatoes about 1.8 g). Another option: place 60 g of smoked salmon on the finished omelet at the end, this pushes the protein up to around 41 g.
Which tips help with a mushroom omelet?
- Do not wash mushrooms, wipe them with a paper towel instead, otherwise they soak up water and turn mushy.
- Let the pan smoke before you add the butter, that way the mushrooms caramelize instead of boiling.
- Whisk the eggs with 1 tbsp of cold water, this makes the omelet fluffier than cream or milk.
- Sprinkle the cheese only once the omelet is half set, on raw egg it will not spread evenly.
- Take the pan off the heat while the surface still looks glossy, residual heat finishes the cook and keeps the omelet juicy.
Nutrition values
| Nutrient | Per 100 g | Per serving | Keto context |
|---|---|---|---|
| Calories | approx. 130 kcal | approx. 430 kcal | Filling breakfast, about 24 % of an 1800 kcal day. |
| Filling breakfast, about 24 % of an 1800 kcal day. | |||
| Fat | approx. 10 g | approx. 32 g | High fat share from yolks, butter, and Gruyère, fully keto-friendly. |
| High fat share from yolks, butter, and Gruyère, fully keto-friendly. | |||
| Net carbs | approx. 1 g | approx. 3 g | Very low, coming from the mushrooms and traces in eggs and cheese. |
| Very low, coming from the mushrooms and traces in eggs and cheese. | |||
| Sugar | < 1 g | approx. 1 g | Negligible, naturally present in the mushrooms. |
| Negligible, naturally present in the mushrooms. | |||
| Protein | approx. 8 g | approx. 28 g | High, covers about 19 % of the daily protein needs for a 75 kg person. |
| High, covers about 19 % of the daily protein needs for a 75 kg person. | |||
| Salt | approx. 0.3 g | approx. 1 g | Moderate, Gruyère adds most of the salt, season sparingly at the end. |
| Moderate, Gruyère adds most of the salt, season sparingly at the end. | |||
Note: Nutrition values are estimated averages per 100 g and per serving and may vary depending on ingredients, brands, portion size, and preparation. They do not replace individual nutrition or medical advice.
FAQ
Can I make the omelet with just 2 eggs?
Yes, the serving then drops to about 320 kcal, 23 g of fat, and 21 g of protein, still a complete keto breakfast. Switch from a 24 cm pan to a 20 cm one, otherwise the omelet becomes too thin and tears when you turn it. With 2 eggs you do not need the 1 tbsp of water, just whisk them on their own.
Which mushrooms work besides white mushrooms?
King oyster mushrooms (sliced) give a firm bite and similar macros (approx. 2.5 g net carbs per 100 g). Porcini are more aromatic but pricier, dried and rehydrated they work too (20 g dried equals roughly 60 g fresh). Chanterelles are great in summer and come in at about 2 g of net carbs per 100 g. Oyster mushrooms are a budget-friendly option.
Does the recipe work without cheese?
Yes, then the fat drops to about 23 g and the protein to 20 g per serving. To make up the fat, bump the butter up to 20 g or place 1/4 of an avocado (40 g) on the finished omelet, adding fiber and monounsaturated fats. If you are lactose intolerant, lactose-free hard cheese or fresh goat cheese also work.
Is the omelet good for weight loss on keto?
Yes, 28 g of protein with 3 g of net carbs and 430 kcal is a well-balanced keto breakfast. Protein keeps you fuller longer than carbs do, and the fat plus protein combo keeps insulin steady. To trim calories, halve the cheese to 20 g and the butter to 10 g, the serving lands at about 350 kcal with 25 g of protein still on board.