Make sauce first,i use small size fresh shitake ,incase use big fresh one first slice it ,slice shallot,finely chop garlic

Fry chopped garlic,onion with butter on low heat until light brown

Add mushroom ,fry until cook ,get good smell

Seasoning with brown sauce powder ,salt and pepper just to taste,not all

Add whipping cream, stir to mix..let it boil if that too thick add milk ,let it cook 3 more mins ,add parsley,heat off

Heat grill pan on medium ,clean and pat dry pork loin ,seasoning with salt and pepper, olive oil..grill approximately 7 mins per each side ,depend on how thick..may be more ..flip and grill until golden ,transfer to cutting board ,let sit 3 mins

Set on serving plate by slice or not as you desire,top with warm mushroom sauce,side with fresh green salad and some choice of pasta (option )