Slice baguettes into 34 pieces and place on a baking sheet, toast at 350º for 7 minutes. Meanwhile heat the olive oil in a wok or large non-stick frying pan. Add mushroom and sauté for about 7 minutes. Add the garlic and stir to combine. Add heavy cream and oyster sauce; bring to a boil. Remove from heat. Stir in the cheese.
Top each piece of toast with 1 spoonful of mushroom, enough to cover the top of the toast. Place on a foil lined baking sheet. Broil on high for 3 minutes, until cheese is melted.