In a large skillet, heat oil over medium-high heat until shimmering. Add mushrooms and cook, stirring frequently, until they begin to brown, release their liquid, and reduce in volume, about 3 minutes.
Reduce heat to medium. Continue cooking, stirring occasionally, until mushrooms are lightly browned and their released liquid begins to cook off, about 2 minutes. Add garlic, ginger powder, fennel, turmeric, paprika, and salt. Stir to evenly coat mushrooms.
Reduce heat to medium-low and cook, stirring frequently, until mushrooms are well browned, very fragrant, and pan is mostly dry, about 2 to 3 minutes. Serve warm or at room temperature.