1. Peel and dice the onion. Wipe and slice the mushrooms. Whisk the eggs, (mineral water,) chives, salt, and pepper together.
2. Optional: Dice the tofu.
3. Heat 1 tsp of oil in a skillet over high heat and sauté the onion for 2 to 3 minutes. Add the mushrooms (and tofu). Sauté everything for 4 to 5 minutes. Season with salt, pepper, and nutmeg. Remove from heat and mix with the cream cheese.
4. Heat the remaining oil in a skillet over high heat, pour in the eggs, and let them solidify for about 3 minutes covered. Add the mushroom and tofu mixture. Fold the omelette in half. Serve.