How to Make It
In a large skillet, heat the olive oil until shimmering. Add the mushrooms and cook over moderately high heat until browned and tender, about 6 minutes. Add the garlic and thyme and cook over moderate heat until fragrant, about 1 minute. Add the spinach and cook just until wilted, about 1 minute. Add the butter and water and swirl the pan until a buttery sauce forms. Remove from the heat and season generously with salt and pepper. Set the toast on plates, spoon the mushrooms and spinach on top and serve.