Dismember a chicken and boil it in pan #1 until tender.
Boil it with onion + carrot + garlic clove, all split, and bay leaf + salt.
In pan #2, melt a few tablespoons of butter and whisk 0.4 dl of wheat flour into it.
Add 5 dl of the chicken broth from pan #1, strained, a little at a time, while whisking.
Add the shredded zest of a lemon and half of its juice.
Add salt and pepper to taste and a dash of turmeric for colour.
When the sauce has boiled for a while and thickened well, take it off the heat and whisk an egg yolk into it.
Meanwhile, cook rice and some vegetables.
The easiest way to keep the chicken warm while you get everything ready is to leave it in the surplus broth.
WARNING: do not add milk or cream to the sauce, as the citric acid will cause them to curdle.
Bo Ohlson is the father of my childhood friend Örjan. He is one of Sweden’s main authorities on pharmaceutical history.