Soup Piazcheh (سوپ پیازچه) — Persian Spring Onion & Oat Soup

• 300 gSpring onions (scallions), finely sliced (white and green parts separated) (About 3 packed cups sliced; reserve 40 g greens for garnish)
• 200 gCarrots, small dice (5 mm) (About 1 1/2 cups diced)
• 200 gWhite button mushrooms, finely chopped (About 2 cups chopped)
• 30 gUnsalted butter (For sautéing; may replace with olive oil)
• 1.5 tspGround turmeric (For color and warmth)
• 2 tspFine sea salt (Plus more to taste; adjust if broth is salty)
• 0.75 tspBlack pepper, freshly ground (Optional but recommended)
• 1200 mlChicken broth (Low-sodium preferred)
• 600 mlWater (Adds volume without over-salting)
• 120 gRolled oats (About 1 1/3 cups; use old-fashioned for best texture)
• 360 mlWhole milk (About 1 1/2 cups; warm slightly before adding)
• 120 mlHeavy cream (About 1/2 cup; for a velvety finish)
• 30 mlFresh lemon juice (About 2 tbsp, plus more to taste)

Instructions

1. 1

   Prep the vegetables: slice spring onions and keep the white/light-green parts separate from the darker greens. Dice the carrots to 5 mm and chop mushrooms finely. Warm the milk in a small saucepan over low heat for 3–4 minutes until just warm (do not simmer), then set aside to prevent curdling later.

2. 2

   In a heavy pot over medium heat, melt the butter for 1 minute until foamy. Add the spring onion whites and light greens, then sauté 5–6 minutes, stirring often, until softened and sweet-smelling but not browned. Stir in turmeric, salt, and black pepper and cook 30 seconds to bloom the spice.

3. 3

   Add carrots and mushrooms to the pot and cook 7–8 minutes over medium heat. Stir every minute so the vegetables soften evenly and the mushrooms release their moisture. You want the mixture glossy and lightly reduced, which builds a deeper broth flavor without needing long simmering.

4. 4

   Pour in the chicken broth and water, scraping the bottom to release any flavorful bits. Increase heat to high and bring to a gentle boil, about 6–8 minutes. Once boiling, reduce to a steady simmer (small bubbles) and cook 10 minutes, partially covered, until carrots are tender.

5. 5

   Stir in the rolled oats in a slow stream to avoid clumping. Simmer 12–15 minutes, stirring every 2–3 minutes, until the oats are fully softened and the soup looks slightly thickened. If the soup becomes too thick, add 60–120 ml water and simmer 2 more minutes.

6. 6

   Lower the heat to low. While stirring constantly, slowly pour in the warmed milk, then add the cream. Keep the soup below a simmer (about 75–85°C / 167–185°F) for 5 minutes, stirring frequently, so it turns creamy and velvety without splitting.

7. 7

   Turn off the heat and stir in lemon juice. Taste and adjust salt and lemon, adding 1/4 tsp salt or 5 ml lemon juice at a time. Ladle into bowls and garnish with the reserved spring onion greens. Rest 5 minutes before serving for the texture to settle and thicken slightly.