I suggest cooking chicken wings with mustard sauce, which, by the way, is great for fish, meat, sausages or vegetables. It is prepared in the likeness of bechamel sauce, that is, very quickly.
Put the chicken wings in a saucepan. Peel the onion, wash it, cut it into half rings, add it to the wings. Then squeeze out the lemon juice, add soy sauce, favorite spices and mix well. Cover with a plate, put the filling on top and leave to marinate for 1-2 hours.
Then put the chicken wings on the grill and cook until browned on the coals.
For the sauce, melt the butter in a saucepan, sift the flour.
Stir so that there are no lumps.
Add milk, salt, spices (you can without them, I have Provencal herbs). Stir constantly, bring to a boil and remove from heat. The sauce will thicken.
Then add the Bavarian mustard and mix. The sauce no longer needs to be boiled.
The sauce can be prepared in advance and taken with you on a picnic.