To make the creamy & delicious mushroom sauce, heat 3 tbsp of butter in a pan and let it sizzle.
Then, add chopped garlic and onions.
Saute till the raw smell of garlic goes away and onions are translucent.
Add sliced mushrooms and cook for about 5 minutes.
Cook till the mushrooms turn soft, brown and loose their moisture for about 5 minutes.
Add sea salt, black pepper and dried thyme and cook for another minute.
Add the milk and heavy cream.
Bring the creamy mushroom gravy to a boil and then simmer till the mushroom sauce becomes thick.