Finely chop the garlic and keep it aside. Slice the onions and mushrooms.
Boil or bake the potatoes and cut them into big cubes.
Heat a pan and add oil. Once it is hot, add finely chopped garlic and thyme sprigs.
Now add sliced onions and let them fry for a couple of minutes.
Add mushrooms and let it cook for 2 minutes on medium to high flame. Mushrooms will start releasing their water.
Now add shiitake mushrooms powder, black pepper powder, salt, and ½ cup water. Mix everything well and let it simmer for 3-4 minutes on medium flame.
Add boiled potato cubes and let them simmer for 5 minutes in mushroom gravy. You can prick potatoes with a fork so that flavors go well into them. You can add more water to adjust the consistency as per your liking.
Switch off the stove, and the sauteed mushrooms with potatoes is ready to serve.