Cut the smoked poultry fillet into dice and transfer to a bowl.
Cut off the roots of the leek and green leaves. Wash the pale part of the leek, remove the outer layer, cut lengthwise in half, then chop into thin half-slices. Place on a colander and blanch with boiling water from a kettle. Drain and cool.
To the bowl with the fillet add drained corn, cucumbers cut into dice, yellow cheese grated on a grater with large holes, and leek.
Add mayonnaise, sour cream, mustard, salt, and pepper. Mix and transfer to a salad bowl, decorate with green leaves.
