Preheat your oven to 375°F (190°C) and grease a baking dish with olive oil.

Sauté chopped mushrooms in olive oil over medium heat for 5-7 minutes until golden brown.

Toast walnuts in another pan over medium heat for about 3-4 minutes until fragrant.

In a large bowl, combine sautéed mushrooms, toasted walnuts, flour, baking powder, thyme, garlic powder, salt, and pepper. Gradually mix in vegetable broth until well combined.

Pour the mixture into the greased baking dish and bake for 30-35 minutes or until golden brown and a toothpick comes out clean.

Let cool slightly before slicing and serve warm.