Frankfurter Grüne Soße

Ingredients

Equipment Needed

• •Sharp chef's knife or mezzaluna
• •Large chopping board
• •Mixing bowl
• •Medium saucepan for potatoes
• •Small saucepan for eggs

Instructions

1. 1

   Cook potatoes

   Put the potatoes in cold salted water and bring them up gently, because starting cold cooks them through to the centre before the skins split. Simmer until a knife slides in cleanly, 18 to 25 minutes depending on size, then drain and let them dry in their own heat so the sauce doesn't slide off watery skins.

2. 2

   Boil eggs

   Lower the eggs into simmering water and cook 9 to 10 minutes for firm yolks. Cool them under cold water so the cooking stops and the yolks stay clean yellow instead of going grey at the edge. Peel and halve them, or chop two into the sauce if your table likes it that way.

   Frankfurt often serves the eggs beside the sauce, not lost inside it. Chopped egg makes the sauce thicker and more filling; halved egg keeps the green clean on the plate.
3. 3

   Mix dairy base

   Stir the sour cream, quark, yoghurt or buttermilk, oil, mustard, lemon juice, vinegar, sugar, a little salt, and black pepper until smooth. The quark gives body, the sour cream gives fat, and the acid sharpens the herbs, so don't make it thin and timid.

4. 4

   Chop herbs

   Wash the herbs only if they need it, then dry them very well. Wet herbs dilute the sauce and make it slack. Slice the chives, snip the cress, and chop the soft herbs finely with a sharp knife; a dull knife bruises the leaves and pushes bitter green juice onto the board instead of into the bowl.

5. 5

   Fold raw herbs

   Fold the chopped herbs into the cold dairy base, turning gently until the sauce is speckled deep green. Keep it raw. Heat would drive off the fresh oils and dull the colour, and a hard puree would make the sauce taste grassy instead of clean.

6. 6

   Rest and taste

   Cover and chill the sauce for 30 minutes, because the dairy needs time to take the herb flavour without losing its cold brightness. Taste after the rest, not before. Add salt, lemon, or pepper only then, since cold dairy mutes seasoning and the herbs keep speaking as they sit.

7. 7

   Serve plainly

   Set the sauce cold over warm or room-temperature boiled potatoes with the hard eggs alongside. The potatoes carry the sauce, the eggs make it a meal, and nothing needs decorating beyond a little extra cress if you kept some back. This is not a show plate. It's supper.

Chef Tips

• •Use the real seven-herb bundle when you can find it: borage, chervil, cress, parsley, salad burnet, sorrel, and chives. Dill is for another argument, not Frankfurt.
• •Dry the herbs hard after washing. Water is the quiet thief here; it thins the dairy, washes out the flavour, and leaves the sauce tasting flat.
• •No heat, no jar, no packet. A bottled green sauce tastes cooked before it starts, and this dish lives on raw herb bite.
• •If one herb is impossible to find, keep the balance sharp and fresh with more chervil, cress, and sorrel. Don't replace the whole thing with parsley and call the matter settled.
• •Serve with waxy potatoes, not floury ones. They hold their shape under the cold sauce, while a floury potato breaks down and turns the plate pasty.

Advance Preparation

• •The sauce can be made 4 to 6 hours ahead and kept covered in the refrigerator. Stir once before serving because the herbs settle into the dairy.
• •Boil the potatoes and eggs earlier the same day. Serve the potatoes warm or room temperature, but keep the sauce cold so the herbs stay bright.
• •Do not freeze Grüne Soße. The dairy breaks and the herbs turn dull, which is not thrift, it's punishment.

Frequently Asked Questions

Nutrition Information

1 serving (about 410g)