Kosher Mushroom and Onion Omelet

Mushroom and onion omelet on white plate.

The Spruce / Miri Rotkovitz

Prep: 5 mins
Cook: 10 mins
Total: 15 mins
Serving: 1 to 2 servings
Nutrition Facts (per serving)
294 Calories
18g Fat
14g Carbs
19g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 1 to 2
Amount per serving
Calories 294
% Daily Value*
Total Fat 18g 23%
Saturated Fat 8g 39%
Cholesterol 470mg 157%
Sodium 375mg 16%
Total Carbohydrate 14g 5%
Dietary Fiber 3g 9%
Protein 19g
Calcium 139mg 11%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

Eggs are wholesome, quick to prepare, and delicious with a variety of fillings, and who doesn't love breakfast for dinner? Omelets are ideal for those evenings when you want a light, yet satisfying entrée, and want to get it on the table fast. Easy prep and construction don't mean you can't linger over the meal—take a cue from the French and serve this savory mushroom and onion omelet with salad, a baguette, and a great glass of wine.

For a dairy omelet, use butter (or a mix of butter and olive oil) and your favorite cheese; substitute olive oil and omit the cheese if you prefer to go dairy-free.

Not much beats a toasted homemade bagel as an omelet accompaniment.


  • 3 large eggs
  • Salt (to taste)
  • 2 teaspoons plus 1 teaspoon unsalted butter (or extra virgin olive oil)
  • 1/2 medium onion (about 3 1/2 ounces / 100 grams; finely chopped)
  • 4 ounces / 125 grams crimini mushrooms (cleaned, trimmed, and thinly sliced; about 1 1/4 cups sliced)
  • Optional: 2 tablespoons shredded cheddar (or other favorite cheese)
  • Optional: freshly snipped chives

Steps to Make It

  1. Crack the eggs into a bowl and add a pinch of salt. Whisk until well beaten, then set aside.

  2. Melt 2 teaspoons of butter (or warm the oil) in a 9- or 10-inch cast iron or heavy nonstick skillet set over medium heat. Add the onions and sauté until soft and translucent, about 3 to 5 minutes. Add the mushrooms and sauté until they release their juices and become soft, about 3 minutes more. Transfer the onions and mushrooms to bowl and set aside.

  3. Wipe out the skillet and add 1 teaspoon of butter or oil, swirling to coat the bottom of the pan. Pour in the beaten eggs. When the edges begin to set, run a silicone or rubber spatula around the circumference, pushing the edge aside slightly, and tilting the pan to let any uncooked egg run under the omelet.

  4. When the surface of the egg is almost entirely set, top one side of the omelet with the reserved sautéed mushrooms and onions. Sprinkle evenly with cheese, if using. Use a spatula to carefully fold the other side of the omelet over the filling. Gently flip the stuffed omelet and cook for another minute, until the cheese melts and the egg is set.

  5. Transfer to a plate and garnish with freshly snipped chives, if desired. Serve immediately.