Hi. What kind of cheese do you use for a mushroom’s julienne? Thank you.

Generally, not strong flavored cheese, as it dominates or drowns out the earthy but usually mild taste of mushrooms.
Most common dairy used with mushrooms is butter or cream, whose fats enhance the mushroom flavor.
If you strongly want to use cheese with mushroom, go for mild-flavored soft or hard-texture cheese...cottage, mozzarella, gouda, havarti etc.