For the asparagus-ham lasagna, peel the asparagus and remove the lower woody third (it’s best to just break it off). Halve lengthwise and cut into thumb-length pieces.
In a pot, boil plenty of salted water with a pinch of sugar and some vinegar. Put the asparagus in and simmer for a maximum of 2 minutes (!), then drain carefully.
Melt butter in a saucepan, stir in flour, toast briefly and slowly pour in milk. Let it boil down again and again until it is a creamy, but not too thick sauce.
Stir in egg yolks.
Season vigorously with salt, pepper, nutmeg and enough turmeric to make the sauce nice and yellow.
Cut ham into strips.
Preheat the oven to 180 °C.
Grease a suitable dish with melted butter, pour in some sauce and put in lasagne sheets. Drizzle with a little sauce, sprinkle with ham strips and asparagus pieces, drizzle again with sauce and cover with lasagne sheets.Repeat until everything is used up.
Cover with sauce and bake in a hot oven for a good half hour.
Sprinkle the asparagus-ham lasagna with grated cheese about 10 minutes before the end of cooking time and bake until golden brown.