Tender Steamed Chicken with Black Bean Sauce

Super easy tender steamed chicken with black bean sauce, inspired by Cantonese steamed ribs with black bean sauce.
Best part hidden at the bottom.
--Ingredients----
4 chicken drumsticks , remove the bones and cut into small pieces
Marinating Ingredients
1 tbsp. Chinese cooking wine
1 tbsp. light soy sauce
1/2 tbsp. oyster sauce , optional
1/4 tsp. sugar
1/4 tsp. white pepper powder
2 spring onions
5 slices of ginger
Others
1 tbsp. cornstarch
4 garlic cloves , finely chopped
1 tbsp. fermented black beans
2 tbsp. vegetable cooking oil , heat until smoky
wood ear mushrooms as needed
other mushroom