Sausage Stuffed Mushrooms With Hollandaise

large capped brown mushrooms (baby portobello or cremini)

olive oil

sweet Italian sausage

green onions, white and green parts, minced

garlic cloves, pressed

panko bread crumbs

Arla Peppercorn or Original cream cheese

Arla Fontina cheese slices, chopped small

freshly grated Parmesan cheese

fresh parsley leaves, minced

Kosher salt and freshly ground black pepper

butter (1 stick)

egg yolks

dry mustard

lemon juice

Tabasco sauce