Omelet-e Tokhm-e Morgh (املت تخم مرغ) — Persian Creamy Vegetable Omelette

• 120 gYellow onion (finely diced)
• 200 gButton mushrooms (cleaned and thinly sliced)
• 180 gRoma tomato (seeded and diced)
• 15 mlVegetable oil (for sautéing)
• 25 gUnsalted butter (divided)
• 12 gAll-purpose flour (about 1 1/2 tablespoons)
• 240 mlWhole milk (warmed (not boiling))
• 4 gSea salt (divided, plus more to taste)
• 1 gBlack pepper (freshly ground)
• 6Large eggs (room temperature)
• 80 gMozzarella cheese (low-moisture, shredded)

Instructions

1. 1

   Prep the vegetables for even cooking: dice the onion finely, slice the mushrooms thinly, and seed and dice the tomato. Warm the milk in a small pot over low heat for 2–3 minutes until steaming (about 50–60°C); keep it warm so the sauce stays smooth and lump-free.

2. 2

   Sauté the vegetables: heat a 24–26 cm nonstick skillet over medium heat for 1 minute, then add vegetable oil and 10 g butter. Add onion with 1 g salt and cook 5–6 minutes, stirring, until translucent and lightly golden. Add mushrooms and cook 6–8 minutes until their moisture evaporates and edges brown.

3. 3

   Add tomato and concentrate flavor: stir in diced tomato with 1 g salt and cook 3–4 minutes until softened and glossy, but not watery. Spread the vegetable mixture into an even layer in the pan, then reduce heat to low while you quickly make the white sauce in a separate small saucepan.

4. 4

   Make the white sauce: melt remaining 15 g butter in a small saucepan over medium-low heat. Whisk in flour and cook 60–90 seconds until it smells lightly nutty but stays pale. Slowly whisk in warm milk in 3 additions, whisking constantly, and simmer 2–3 minutes until thick enough to coat a spoon.

5. 5

   Season and combine: whisk black pepper and remaining 2 g salt into the white sauce, then pour the sauce over the vegetables in the skillet. Stir gently for 30–45 seconds to coat everything evenly. Keep heat low; the mixture should be creamy, not boiling, to prevent the eggs from tightening too fast.

6. 6

   Cook the omelette gently: beat eggs in a bowl for 20–30 seconds until yolks and whites are fully blended (avoid over-whipping). Pour eggs into the skillet and stir slowly with a silicone spatula for 45–60 seconds, scraping the bottom, then stop stirring and let it set 3–4 minutes on low.

7. 7

   Melt cheese and finish: sprinkle mozzarella evenly over the top. Cover with a lid and cook 2–3 minutes on low until the cheese melts and the center reaches a soft-set texture (eggs should look glossy, not wet). Rest off heat, covered, for 2 minutes for carryover setting before slicing.