Heat olive oil in a skillet over medium heat. Add onions and cook until translucent. Add garlic and cook for 1 more minute.
Add mushrooms, including any accumulated juices. Cook until softened, about 10 minutes. Season with salt and pepper.
Sprinkle flour over veggies. Stir to coat evenly. Cook for an additional 2 minutes.
In a food processor, blend soaked cashews, coconut milk, miso, nutritional yeast, lemon juice, and seasonings until very smooth and creamy.
Transfer mushroom mixture from the skillet to the food processor. Pulse just until incorporated but still chunky.
Transfer to an oven-safe dish. Bake at 400°F for 20 minutes until bubbly.
Garnish with parsley. Serve immediately with chips, crackers, or raw veggies.