In a bowl, combine all the ingredients for the steak spices. (You can double or triple the portion to prepare more for other recipes)
10 button mushrooms, 1 tbsp. steak spices, 2 tbsp paprika, 2 tbsp freshly ground black pepper, 2 tbsp sea salt, 1 tbsp garlic powder, 1 tbsp onion powder, 1 tbsp crushed coriander seeds