Add your dehydrated mushrooms to some boiling water and allow to re-hydrate for about 10-15 minutes.
While the mushrooms re-hydrate slice your baguette into rounds and place on a baking sheet. You can optionally drizzle some sesame oil over them for some extra flavour. Bake for about 10 minutes or until toasted.
Slice up your mushrooms and add to a hot pan with sesame oil, soy sauce, garlic powder, onion powder, fresh rosemary and a sprinkle of sesame seeds. Toss until coated in all the flavours and spices. Sautee until heated, approximately 10 minutes.
Spread some vegan cream cheese on each crostini, top with some of the sauteed mushrooms and sprinkle with some sesame seeds.